200 files changed, 5093 insertions, 4318 deletions

diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index 24d04e51f..10b930e4f 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -23,10 +23,10 @@
 #define AK_FORCE_INLINE inline
 #endif // __GNUC__
 
-#if defined(FLAG_DO_PROFILE) || defined(FLAG_DBG)
+#if defined(FLAG_DBG)
 #undef AK_FORCE_INLINE
 #define AK_FORCE_INLINE inline
-#endif // defined(FLAG_DO_PROFILE) || defined(FLAG_DBG)
+#endif // defined(FLAG_DBG)
 
 // Must be equal to Constants.Dictionary.MAX_WORD_LENGTH in Java
 #define MAX_WORD_LENGTH 48
@@ -119,7 +119,7 @@ static inline void dumpWordInfo(const int *word, const int length, const int ran
         const int probability) {
     static char charBuf[50];
     const int N = intArrayToCharArray(word, length, charBuf, NELEMS(charBuf));
-    if (N > 1) {
+    if (N > 0) {
         AKLOGI("%2d [ %s ] (%d)", rank, charBuf, probability);
     }
 }
@@ -172,69 +172,6 @@ static inline void showStackTrace() {
 #define INTS_TO_CHARS(input, length, output)
 #endif // defined(FLAG_DO_PROFILE) || defined(FLAG_DBG)
 
-#ifdef FLAG_DO_PROFILE
-// Profiler
-#include <time.h>
-
-#define PROF_BUF_SIZE 100
-static float profile_buf[PROF_BUF_SIZE];
-static float profile_old[PROF_BUF_SIZE];
-static unsigned int profile_counter[PROF_BUF_SIZE];
-
-#define PROF_RESET               prof_reset()
-#define PROF_COUNT(prof_buf_id)  ++profile_counter[prof_buf_id]
-#define PROF_OPEN                do { PROF_RESET; PROF_START(PROF_BUF_SIZE - 1); } while (0)
-#define PROF_START(prof_buf_id)  do { \
-        PROF_COUNT(prof_buf_id); profile_old[prof_buf_id] = (clock()); } while (0)
-#define PROF_CLOSE               do { PROF_END(PROF_BUF_SIZE - 1); PROF_OUTALL; } while (0)
-#define PROF_END(prof_buf_id)    profile_buf[prof_buf_id] += ((clock()) - profile_old[prof_buf_id])
-#define PROF_CLOCKOUT(prof_buf_id) \
-        AKLOGI("%s : clock is %f", __FUNCTION__, (clock() - profile_old[prof_buf_id]))
-#define PROF_OUTALL              do { AKLOGI("--- %s ---", __FUNCTION__); prof_out(); } while (0)
-
-static inline void prof_reset(void) {
-    for (int i = 0; i < PROF_BUF_SIZE; ++i) {
-        profile_buf[i] = 0;
-        profile_old[i] = 0;
-        profile_counter[i] = 0;
-    }
-}
-
-static inline void prof_out(void) {
-    if (profile_counter[PROF_BUF_SIZE - 1] != 1) {
-        AKLOGI("Error: You must call PROF_OPEN before PROF_CLOSE.");
-    }
-    AKLOGI("Total time is %6.3f ms.",
-            profile_buf[PROF_BUF_SIZE - 1] * 1000.0f / static_cast<float>(CLOCKS_PER_SEC));
-    float all = 0.0f;
-    for (int i = 0; i < PROF_BUF_SIZE - 1; ++i) {
-        all += profile_buf[i];
-    }
-    if (all < 1.0f) all = 1.0f;
-    for (int i = 0; i < PROF_BUF_SIZE - 1; ++i) {
-        if (profile_buf[i] > 0.0f) {
-            AKLOGI("(%d): Used %4.2f%%, %8.4f ms. Called %d times.",
-                    i, (profile_buf[i] * 100.0f / all),
-                    profile_buf[i] * 1000.0f / static_cast<float>(CLOCKS_PER_SEC),
-                    profile_counter[i]);
-        }
-    }
-}
-
-#else // FLAG_DO_PROFILE
-#define PROF_BUF_SIZE 0
-#define PROF_RESET
-#define PROF_COUNT(prof_buf_id)
-#define PROF_OPEN
-#define PROF_START(prof_buf_id)
-#define PROF_CLOSE
-#define PROF_END(prof_buf_id)
-#define PROF_CLOCK_OUT(prof_buf_id)
-#define PROF_CLOCKOUT(prof_buf_id)
-#define PROF_OUTALL
-
-#endif // FLAG_DO_PROFILE
-
 #ifdef FLAG_DBG
 #define DEBUG_DICT true
 #define DEBUG_DICT_FULL false
@@ -299,8 +236,9 @@ static inline void prof_out(void) {
 #define NOT_AN_INDEX (-1)
 #define NOT_A_PROBABILITY (-1)
 #define NOT_A_DICT_POS (S_INT_MIN)
+#define NOT_A_WORD_ID (S_INT_MIN)
 #define NOT_A_TIMESTAMP (-1)
-#define NOT_A_LANGUAGE_WEIGHT (-1.0f)
+#define NOT_A_WEIGHT_OF_LANG_MODEL_VS_SPATIAL_MODEL (-1.0f)
 
 // A special value to mean the first word confidence makes no sense in this case,
 // e.g. this is not a multi-word suggestion.
@@ -337,7 +275,7 @@ static inline void prof_out(void) {
 #define MAX_POINTER_COUNT_G 2
 
 // (MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1)-gram is supported.
-#define MAX_PREV_WORD_COUNT_FOR_N_GRAM 1
+#define MAX_PREV_WORD_COUNT_FOR_N_GRAM 3
 
 #define DISALLOW_DEFAULT_CONSTRUCTOR(TypeName) \
   TypeName() = delete
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp b/native/jni/src/dictionary/header/header_policy.cpp
index 6ed65d921..d4f84d39f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.cpp
+++ b/native/jni/src/dictionary/header/header_policy.cpp
@@ -14,10 +14,12 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "dictionary/header/header_policy.h"
 
 #include <algorithm>
 
+#include "utils/ngram_utils.h"
+
 namespace latinime {
 
 // Note that these are corresponding definitions in Java side in DictionaryHeader.
@@ -28,33 +30,23 @@ const char *const HeaderPolicy::REQUIRES_GERMAN_UMLAUT_PROCESSING_KEY =
 const char *const HeaderPolicy::IS_DECAYING_DICT_KEY = "USES_FORGETTING_CURVE";
 const char *const HeaderPolicy::DATE_KEY = "date";
 const char *const HeaderPolicy::LAST_DECAYED_TIME_KEY = "LAST_DECAYED_TIME";
-const char *const HeaderPolicy::UNIGRAM_COUNT_KEY = "UNIGRAM_COUNT";
-const char *const HeaderPolicy::BIGRAM_COUNT_KEY = "BIGRAM_COUNT";
+const char *const HeaderPolicy::NGRAM_COUNT_KEYS[] =
+        {"UNIGRAM_COUNT", "BIGRAM_COUNT", "TRIGRAM_COUNT", "QUADGRAM_COUNT"};
+const char *const HeaderPolicy::MAX_NGRAM_COUNT_KEYS[] =
+        {"MAX_UNIGRAM_ENTRY_COUNT", "MAX_BIGRAM_ENTRY_COUNT", "MAX_TRIGRAM_ENTRY_COUNT",
+                "MAX_QUADGRAM_ENTRY_COUNT"};
+const int HeaderPolicy::DEFAULT_MAX_NGRAM_COUNTS[] = {10000, 30000, 30000, 30000};
 const char *const HeaderPolicy::EXTENDED_REGION_SIZE_KEY = "EXTENDED_REGION_SIZE";
 // Historical info is information that is needed to support decaying such as timestamp, level and
 // count.
 const char *const HeaderPolicy::HAS_HISTORICAL_INFO_KEY = "HAS_HISTORICAL_INFO";
 const char *const HeaderPolicy::LOCALE_KEY = "locale"; // match Java declaration
-const char *const HeaderPolicy::FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY =
-        "FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP";
 const char *const HeaderPolicy::FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY =
         "FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID";
-const char *const HeaderPolicy::FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY =
-        "FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS";
-
-const char *const HeaderPolicy::MAX_UNIGRAM_COUNT_KEY = "MAX_UNIGRAM_COUNT";
-const char *const HeaderPolicy::MAX_BIGRAM_COUNT_KEY = "MAX_BIGRAM_COUNT";
 
 const int HeaderPolicy::DEFAULT_MULTIPLE_WORDS_DEMOTION_RATE = 100;
 const float HeaderPolicy::MULTIPLE_WORD_COST_MULTIPLIER_SCALE = 100.0f;
-const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP = 2;
 const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID = 3;
-// 30 days
-const int HeaderPolicy::DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS =
-        30 * 24 * 60 * 60;
-
-const int HeaderPolicy::DEFAULT_MAX_UNIGRAM_COUNT = 10000;
-const int HeaderPolicy::DEFAULT_MAX_BIGRAM_COUNT = 10000;
 
 // Used for logging. Question mark is used to indicate that the key is not found.
 void HeaderPolicy::readHeaderValueOrQuestionMark(const char *const key, int *outValue,
@@ -100,12 +92,11 @@ bool HeaderPolicy::readRequiresGermanUmlautProcessing() const {
 }
 
 bool HeaderPolicy::fillInAndWriteHeaderToBuffer(const bool updatesLastDecayedTime,
-        const int unigramCount, const int bigramCount,
-        const int extendedRegionSize, BufferWithExtendableBuffer *const outBuffer) const {
+        const EntryCounts &entryCounts, const int extendedRegionSize,
+        BufferWithExtendableBuffer *const outBuffer) const {
     int writingPos = 0;
     DictionaryHeaderStructurePolicy::AttributeMap attributeMapToWrite(mAttributeMap);
-    fillInHeader(updatesLastDecayedTime, unigramCount, bigramCount,
-            extendedRegionSize, &attributeMapToWrite);
+    fillInHeader(updatesLastDecayedTime, entryCounts, extendedRegionSize, &attributeMapToWrite);
     if (!HeaderReadWriteUtils::writeDictionaryVersion(outBuffer, mDictFormatVersion,
             &writingPos)) {
         return false;
@@ -132,11 +123,22 @@ bool HeaderPolicy::fillInAndWriteHeaderToBuffer(const bool updatesLastDecayedTim
     return true;
 }
 
-void HeaderPolicy::fillInHeader(const bool updatesLastDecayedTime, const int unigramCount,
-        const int bigramCount, const int extendedRegionSize,
+namespace {
+
+int getIndexFromNgramType(const NgramType ngramType) {
+    return static_cast<int>(ngramType);
+}
+
+} // namespace
+
+void HeaderPolicy::fillInHeader(const bool updatesLastDecayedTime,
+        const EntryCounts &entryCounts, const int extendedRegionSize,
         DictionaryHeaderStructurePolicy::AttributeMap *outAttributeMap) const {
-    HeaderReadWriteUtils::setIntAttribute(outAttributeMap, UNIGRAM_COUNT_KEY, unigramCount);
-    HeaderReadWriteUtils::setIntAttribute(outAttributeMap, BIGRAM_COUNT_KEY, bigramCount);
+    for (const auto ngramType : AllNgramTypes::ASCENDING) {
+        HeaderReadWriteUtils::setIntAttribute(outAttributeMap,
+                NGRAM_COUNT_KEYS[getIndexFromNgramType(ngramType)],
+                entryCounts.getNgramCount(ngramType));
+    }
     HeaderReadWriteUtils::setIntAttribute(outAttributeMap, EXTENDED_REGION_SIZE_KEY,
             extendedRegionSize);
     // Set the current time as the generation time.
@@ -157,4 +159,25 @@ void HeaderPolicy::fillInHeader(const bool updatesLastDecayedTime, const int uni
     return attributeMap;
 }
 
+/* static */ const EntryCounts HeaderPolicy::readNgramCounts() const {
+    MutableEntryCounters entryCounters;
+    for (const auto ngramType : AllNgramTypes::ASCENDING) {
+        const int entryCount = HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
+                NGRAM_COUNT_KEYS[getIndexFromNgramType(ngramType)], 0 /* defaultValue */);
+        entryCounters.setNgramCount(ngramType, entryCount);
+    }
+    return entryCounters.getEntryCounts();
+}
+
+/* static */ const EntryCounts HeaderPolicy::readMaxNgramCounts() const {
+    MutableEntryCounters entryCounters;
+    for (const auto ngramType : AllNgramTypes::ASCENDING) {
+        const int index = getIndexFromNgramType(ngramType);
+        const int maxEntryCount = HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
+                MAX_NGRAM_COUNT_KEYS[index], DEFAULT_MAX_NGRAM_COUNTS[index]);
+        entryCounters.setNgramCount(ngramType, maxEntryCount);
+    }
+    return entryCounters.getEntryCounts();
+}
+
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h b/native/jni/src/dictionary/header/header_policy.h
index 87cf0cd3b..47cc9196a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
+++ b/native/jni/src/dictionary/header/header_policy.h
@@ -20,9 +20,10 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/policyimpl/dictionary/header/header_read_write_utils.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "dictionary/header/header_read_write_utils.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/utils/entry_counters.h"
+#include "dictionary/utils/format_utils.h"
 #include "utils/char_utils.h"
 #include "utils/time_keeper.h"
 
@@ -45,27 +46,15 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
                       DATE_KEY, TimeKeeper::peekCurrentTime() /* defaultValue */)),
               mLastDecayedTime(HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
                       LAST_DECAYED_TIME_KEY, TimeKeeper::peekCurrentTime() /* defaultValue */)),
-              mUnigramCount(HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
-                      UNIGRAM_COUNT_KEY, 0 /* defaultValue */)),
-              mBigramCount(HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
-                      BIGRAM_COUNT_KEY, 0 /* defaultValue */)),
+              mNgramCounts(readNgramCounts()), mMaxNgramCounts(readMaxNgramCounts()),
               mExtendedRegionSize(HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
                       EXTENDED_REGION_SIZE_KEY, 0 /* defaultValue */)),
               mHasHistoricalInfoOfWords(HeaderReadWriteUtils::readBoolAttributeValue(
                       &mAttributeMap, HAS_HISTORICAL_INFO_KEY, false /* defaultValue */)),
-              mForgettingCurveOccurrencesToLevelUp(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY,
-                      DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP)),
               mForgettingCurveProbabilityValuesTableId(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY,
                       DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID)),
-              mForgettingCurveDurationToLevelDown(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY,
-                      DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS)),
-              mMaxUnigramCount(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, MAX_UNIGRAM_COUNT_KEY, DEFAULT_MAX_UNIGRAM_COUNT)),
-              mMaxBigramCount(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, MAX_BIGRAM_COUNT_KEY, DEFAULT_MAX_BIGRAM_COUNT)) {}
+              mCodePointTable(HeaderReadWriteUtils::readCodePointTable(&mAttributeMap)) {}
 
     // Constructs header information using an attribute map.
     HeaderPolicy(const FormatUtils::FORMAT_VERSION dictFormatVersion,
@@ -82,22 +71,14 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
                       DATE_KEY, TimeKeeper::peekCurrentTime() /* defaultValue */)),
               mLastDecayedTime(HeaderReadWriteUtils::readIntAttributeValue(&mAttributeMap,
                       DATE_KEY, TimeKeeper::peekCurrentTime() /* defaultValue */)),
-              mUnigramCount(0), mBigramCount(0), mExtendedRegionSize(0),
+              mNgramCounts(readNgramCounts()), mMaxNgramCounts(readMaxNgramCounts()),
+              mExtendedRegionSize(0),
               mHasHistoricalInfoOfWords(HeaderReadWriteUtils::readBoolAttributeValue(
                       &mAttributeMap, HAS_HISTORICAL_INFO_KEY, false /* defaultValue */)),
-              mForgettingCurveOccurrencesToLevelUp(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY,
-                      DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP)),
               mForgettingCurveProbabilityValuesTableId(HeaderReadWriteUtils::readIntAttributeValue(
                       &mAttributeMap, FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY,
                       DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID)),
-              mForgettingCurveDurationToLevelDown(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY,
-                      DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS)),
-              mMaxUnigramCount(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, MAX_UNIGRAM_COUNT_KEY, DEFAULT_MAX_UNIGRAM_COUNT)),
-              mMaxBigramCount(HeaderReadWriteUtils::readIntAttributeValue(
-                      &mAttributeMap, MAX_BIGRAM_COUNT_KEY, DEFAULT_MAX_BIGRAM_COUNT)) {}
+              mCodePointTable(HeaderReadWriteUtils::readCodePointTable(&mAttributeMap)) {}
 
     // Copy header information
     HeaderPolicy(const HeaderPolicy *const headerPolicy)
@@ -108,27 +89,22 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
               mRequiresGermanUmlautProcessing(headerPolicy->mRequiresGermanUmlautProcessing),
               mIsDecayingDict(headerPolicy->mIsDecayingDict),
               mDate(headerPolicy->mDate), mLastDecayedTime(headerPolicy->mLastDecayedTime),
-              mUnigramCount(headerPolicy->mUnigramCount), mBigramCount(headerPolicy->mBigramCount),
+              mNgramCounts(headerPolicy->mNgramCounts),
+              mMaxNgramCounts(headerPolicy->mMaxNgramCounts),
               mExtendedRegionSize(headerPolicy->mExtendedRegionSize),
               mHasHistoricalInfoOfWords(headerPolicy->mHasHistoricalInfoOfWords),
-              mForgettingCurveOccurrencesToLevelUp(
-                      headerPolicy->mForgettingCurveOccurrencesToLevelUp),
               mForgettingCurveProbabilityValuesTableId(
                       headerPolicy->mForgettingCurveProbabilityValuesTableId),
-              mForgettingCurveDurationToLevelDown(
-                      headerPolicy->mForgettingCurveDurationToLevelDown),
-              mMaxUnigramCount(headerPolicy->mMaxUnigramCount),
-              mMaxBigramCount(headerPolicy->mMaxBigramCount) {}
+              mCodePointTable(headerPolicy->mCodePointTable) {}
 
     // Temporary dummy header.
     HeaderPolicy()
             : mDictFormatVersion(FormatUtils::UNKNOWN_VERSION), mDictionaryFlags(0), mSize(0),
               mAttributeMap(), mLocale(CharUtils::EMPTY_STRING), mMultiWordCostMultiplier(0.0f),
               mRequiresGermanUmlautProcessing(false), mIsDecayingDict(false),
-              mDate(0), mLastDecayedTime(0), mUnigramCount(0), mBigramCount(0),
+              mDate(0), mLastDecayedTime(0), mNgramCounts(), mMaxNgramCounts(),
               mExtendedRegionSize(0), mHasHistoricalInfoOfWords(false),
-              mForgettingCurveOccurrencesToLevelUp(0), mForgettingCurveProbabilityValuesTableId(0),
-              mForgettingCurveDurationToLevelDown(0), mMaxUnigramCount(0), mMaxBigramCount(0) {}
+              mForgettingCurveProbabilityValuesTableId(0), mCodePointTable(nullptr) {}
 
     ~HeaderPolicy() {}
 
@@ -138,13 +114,17 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
         // same so we use them for both here.
         switch (mDictFormatVersion) {
             case FormatUtils::VERSION_2:
-                return FormatUtils::VERSION_2;
+            case FormatUtils::VERSION_201:
+                AKLOGE("Dictionary versions 2 and 201 are incompatible with this version");
+                return FormatUtils::UNKNOWN_VERSION;
+            case FormatUtils::VERSION_202:
+                return FormatUtils::VERSION_202;
             case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
                 return FormatUtils::VERSION_4_ONLY_FOR_TESTING;
-            case FormatUtils::VERSION_4:
-                return FormatUtils::VERSION_4;
-            case FormatUtils::VERSION_4_DEV:
-                return FormatUtils::VERSION_4_DEV;
+            case FormatUtils::VERSION_402:
+                return FormatUtils::VERSION_402;
+            case FormatUtils::VERSION_403:
+                return FormatUtils::VERSION_403;
             default:
                 return FormatUtils::UNKNOWN_VERSION;
         }
@@ -186,12 +166,12 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
         return mLastDecayedTime;
     }
 
-    AK_FORCE_INLINE int getUnigramCount() const {
-        return mUnigramCount;
+    AK_FORCE_INLINE const EntryCounts &getNgramCounts() const {
+        return mNgramCounts;
     }
 
-    AK_FORCE_INLINE int getBigramCount() const {
-        return mBigramCount;
+    AK_FORCE_INLINE const EntryCounts getMaxNgramCounts() const {
+        return mMaxNgramCounts;
     }
 
     AK_FORCE_INLINE int getExtendedRegionSize() const {
@@ -211,35 +191,19 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
         return &mAttributeMap;
     }
 
-    AK_FORCE_INLINE int getForgettingCurveOccurrencesToLevelUp() const {
-        return mForgettingCurveOccurrencesToLevelUp;
-    }
-
     AK_FORCE_INLINE int getForgettingCurveProbabilityValuesTableId() const {
         return mForgettingCurveProbabilityValuesTableId;
     }
 
-    AK_FORCE_INLINE int getForgettingCurveDurationToLevelDown() const {
-        return mForgettingCurveDurationToLevelDown;
-    }
-
-    AK_FORCE_INLINE int getMaxUnigramCount() const {
-        return mMaxUnigramCount;
-    }
-
-    AK_FORCE_INLINE int getMaxBigramCount() const {
-        return mMaxBigramCount;
-    }
-
     void readHeaderValueOrQuestionMark(const char *const key,
             int *outValue, int outValueSize) const;
 
     bool fillInAndWriteHeaderToBuffer(const bool updatesLastDecayedTime,
-            const int unigramCount, const int bigramCount,
-            const int extendedRegionSize, BufferWithExtendableBuffer *const outBuffer) const;
+            const EntryCounts &entryCounts, const int extendedRegionSize,
+            BufferWithExtendableBuffer *const outBuffer) const;
 
-    void fillInHeader(const bool updatesLastDecayedTime,
-            const int unigramCount, const int bigramCount, const int extendedRegionSize,
+    void fillInHeader(const bool updatesLastDecayedTime, const EntryCounts &entryCounts,
+            const int extendedRegionSize,
             DictionaryHeaderStructurePolicy::AttributeMap *outAttributeMap) const;
 
     AK_FORCE_INLINE const std::vector<int> *getLocale() const {
@@ -247,7 +211,11 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
     }
 
     bool supportsBeginningOfSentence() const {
-        return mDictFormatVersion >= FormatUtils::VERSION_4;
+        return mDictFormatVersion >= FormatUtils::VERSION_402;
+    }
+
+    const int *getCodePointTable() const {
+        return mCodePointTable;
     }
 
  private:
@@ -258,23 +226,18 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
     static const char *const IS_DECAYING_DICT_KEY;
     static const char *const DATE_KEY;
     static const char *const LAST_DECAYED_TIME_KEY;
-    static const char *const UNIGRAM_COUNT_KEY;
-    static const char *const BIGRAM_COUNT_KEY;
+    static const char *const NGRAM_COUNT_KEYS[];
+    static const char *const MAX_NGRAM_COUNT_KEYS[];
+    static const int DEFAULT_MAX_NGRAM_COUNTS[];
     static const char *const EXTENDED_REGION_SIZE_KEY;
     static const char *const HAS_HISTORICAL_INFO_KEY;
     static const char *const LOCALE_KEY;
     static const char *const FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP_KEY;
     static const char *const FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID_KEY;
     static const char *const FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS_KEY;
-    static const char *const MAX_UNIGRAM_COUNT_KEY;
-    static const char *const MAX_BIGRAM_COUNT_KEY;
     static const int DEFAULT_MULTIPLE_WORDS_DEMOTION_RATE;
     static const float MULTIPLE_WORD_COST_MULTIPLIER_SCALE;
-    static const int DEFAULT_FORGETTING_CURVE_OCCURRENCES_TO_LEVEL_UP;
     static const int DEFAULT_FORGETTING_CURVE_PROBABILITY_VALUES_TABLE_ID;
-    static const int DEFAULT_FORGETTING_CURVE_DURATION_TO_LEVEL_DOWN_IN_SECONDS;
-    static const int DEFAULT_MAX_UNIGRAM_COUNT;
-    static const int DEFAULT_MAX_BIGRAM_COUNT;
 
     const FormatUtils::FORMAT_VERSION mDictFormatVersion;
     const HeaderReadWriteUtils::DictionaryFlags mDictionaryFlags;
@@ -286,20 +249,18 @@ class HeaderPolicy : public DictionaryHeaderStructurePolicy {
     const bool mIsDecayingDict;
     const int mDate;
     const int mLastDecayedTime;
-    const int mUnigramCount;
-    const int mBigramCount;
+    const EntryCounts mNgramCounts;
+    const EntryCounts mMaxNgramCounts;
     const int mExtendedRegionSize;
     const bool mHasHistoricalInfoOfWords;
-    const int mForgettingCurveOccurrencesToLevelUp;
     const int mForgettingCurveProbabilityValuesTableId;
-    const int mForgettingCurveDurationToLevelDown;
-    const int mMaxUnigramCount;
-    const int mMaxBigramCount;
+    const int *const mCodePointTable;
 
     const std::vector<int> readLocale() const;
     float readMultipleWordCostMultiplier() const;
     bool readRequiresGermanUmlautProcessing() const;
-
+    const EntryCounts readNgramCounts() const;
+    const EntryCounts readMaxNgramCounts() const;
     static DictionaryHeaderStructurePolicy::AttributeMap createAttributeMapAndReadAllAttributes(
             const uint8_t *const dictBuf);
 };
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp b/native/jni/src/dictionary/header/header_read_write_utils.cpp
index a8f8f284b..779f8b8c3 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp
+++ b/native/jni/src/dictionary/header/header_read_write_utils.cpp
@@ -14,15 +14,16 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/header/header_read_write_utils.h"
+#include "dictionary/header/header_read_write_utils.h"
 
 #include <cctype>
 #include <cstdio>
+#include <memory>
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
@@ -34,12 +35,13 @@ namespace latinime {
 const int HeaderReadWriteUtils::LARGEST_INT_DIGIT_COUNT = 11;
 
 const int HeaderReadWriteUtils::MAX_ATTRIBUTE_KEY_LENGTH = 256;
-const int HeaderReadWriteUtils::MAX_ATTRIBUTE_VALUE_LENGTH = 256;
+const int HeaderReadWriteUtils::MAX_ATTRIBUTE_VALUE_LENGTH = 2048;
 
 const int HeaderReadWriteUtils::HEADER_MAGIC_NUMBER_SIZE = 4;
 const int HeaderReadWriteUtils::HEADER_DICTIONARY_VERSION_SIZE = 2;
 const int HeaderReadWriteUtils::HEADER_FLAG_SIZE = 2;
 const int HeaderReadWriteUtils::HEADER_SIZE_FIELD_SIZE = 4;
+const char *const HeaderReadWriteUtils::CODE_POINT_TABLE_KEY = "codePointTable";
 
 const HeaderReadWriteUtils::DictionaryFlags HeaderReadWriteUtils::NO_FLAGS = 0;
 
@@ -73,20 +75,32 @@ typedef DictionaryHeaderStructurePolicy::AttributeMap AttributeMap;
         return;
     }
     int keyBuffer[MAX_ATTRIBUTE_KEY_LENGTH];
-    int valueBuffer[MAX_ATTRIBUTE_VALUE_LENGTH];
+    std::unique_ptr<int[]> valueBuffer(new int[MAX_ATTRIBUTE_VALUE_LENGTH]);
     while (pos < headerSize) {
+        // The values in the header don't use the code point table for their encoding.
         const int keyLength = ByteArrayUtils::readStringAndAdvancePosition(dictBuf,
-                MAX_ATTRIBUTE_KEY_LENGTH, keyBuffer, &pos);
+                MAX_ATTRIBUTE_KEY_LENGTH, nullptr /* codePointTable */, keyBuffer, &pos);
         std::vector<int> key;
         key.insert(key.end(), keyBuffer, keyBuffer + keyLength);
         const int valueLength = ByteArrayUtils::readStringAndAdvancePosition(dictBuf,
-                MAX_ATTRIBUTE_VALUE_LENGTH, valueBuffer, &pos);
+                MAX_ATTRIBUTE_VALUE_LENGTH, nullptr /* codePointTable */, valueBuffer.get(), &pos);
         std::vector<int> value;
-        value.insert(value.end(), valueBuffer, valueBuffer + valueLength);
+        value.insert(value.end(), valueBuffer.get(), valueBuffer.get() + valueLength);
         headerAttributes->insert(AttributeMap::value_type(key, value));
     }
 }
 
+/* static */ const int *HeaderReadWriteUtils::readCodePointTable(
+        AttributeMap *const headerAttributes) {
+    AttributeMap::key_type keyVector;
+    insertCharactersIntoVector(CODE_POINT_TABLE_KEY, &keyVector);
+    AttributeMap::const_iterator it = headerAttributes->find(keyVector);
+    if (it == headerAttributes->end()) {
+        return nullptr;
+    }
+    return it->second.data();
+}
+
 /* static */ bool HeaderReadWriteUtils::writeDictionaryVersion(
         BufferWithExtendableBuffer *const buffer, const FormatUtils::FORMAT_VERSION version,
         int *const writingPos) {
@@ -96,11 +110,13 @@ typedef DictionaryHeaderStructurePolicy::AttributeMap AttributeMap;
     }
     switch (version) {
         case FormatUtils::VERSION_2:
-            // Version 2 dictionary writing is not supported.
+        case FormatUtils::VERSION_201:
+        case FormatUtils::VERSION_202:
+            // None of the static dictionaries (v2x) support writing
             return false;
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
-        case FormatUtils::VERSION_4:
-        case FormatUtils::VERSION_4_DEV:
+        case FormatUtils::VERSION_402:
+        case FormatUtils::VERSION_403:
             return buffer->writeUintAndAdvancePosition(version /* data */,
                     HEADER_DICTIONARY_VERSION_SIZE, writingPos);
         default:
@@ -142,7 +158,8 @@ typedef DictionaryHeaderStructurePolicy::AttributeMap AttributeMap;
 }
 
 /* static */ void HeaderReadWriteUtils::setCodePointVectorAttribute(
-        AttributeMap *const headerAttributes, const char *const key, const std::vector<int> value) {
+        AttributeMap *const headerAttributes, const char *const key,
+        const std::vector<int> &value) {
     AttributeMap::key_type keyVector;
     insertCharactersIntoVector(key, &keyVector);
     (*headerAttributes)[keyVector] = value;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.h b/native/jni/src/dictionary/header/header_read_write_utils.h
index 9b90488fc..f67d614df 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.h
+++ b/native/jni/src/dictionary/header/header_read_write_utils.h
@@ -20,8 +20,8 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/utils/format_utils.h"
 
 namespace latinime {
 
@@ -46,6 +46,9 @@ class HeaderReadWriteUtils {
     static void fetchAllHeaderAttributes(const uint8_t *const dictBuf,
             DictionaryHeaderStructurePolicy::AttributeMap *const headerAttributes);
 
+    static const int *readCodePointTable(
+            DictionaryHeaderStructurePolicy::AttributeMap *const headerAttributes);
+
     static bool writeDictionaryVersion(BufferWithExtendableBuffer *const buffer,
             const FormatUtils::FORMAT_VERSION version, int *const writingPos);
 
@@ -64,7 +67,7 @@ class HeaderReadWriteUtils {
      */
     static void setCodePointVectorAttribute(
             DictionaryHeaderStructurePolicy::AttributeMap *const headerAttributes,
-            const char *const key, const std::vector<int> value);
+            const char *const key, const std::vector<int> &value);
 
     static void setBoolAttribute(
             DictionaryHeaderStructurePolicy::AttributeMap *const headerAttributes,
@@ -101,6 +104,8 @@ class HeaderReadWriteUtils {
     static const int HEADER_FLAG_SIZE;
     static const int HEADER_SIZE_FIELD_SIZE;
 
+    static const char *const CODE_POINT_TABLE_KEY;
+
     // Value for the "flags" field. It's unused at the moment.
     static const DictionaryFlags NO_FLAGS;
 
diff --git a/native/jni/src/suggest/core/policy/dictionary_bigrams_structure_policy.h b/native/jni/src/dictionary/interface/dictionary_bigrams_structure_policy.h
index aa0d068aa..aa0d068aa 100644
--- a/native/jni/src/suggest/core/policy/dictionary_bigrams_structure_policy.h
+++ b/native/jni/src/dictionary/interface/dictionary_bigrams_structure_policy.h
diff --git a/native/jni/src/suggest/core/policy/dictionary_header_structure_policy.h b/native/jni/src/dictionary/interface/dictionary_header_structure_policy.h
index 6da390e55..6da390e55 100644
--- a/native/jni/src/suggest/core/policy/dictionary_header_structure_policy.h
+++ b/native/jni/src/dictionary/interface/dictionary_header_structure_policy.h
diff --git a/native/jni/src/suggest/core/policy/dictionary_shortcuts_structure_policy.h b/native/jni/src/dictionary/interface/dictionary_shortcuts_structure_policy.h
index 40b6c2de1..40b6c2de1 100644
--- a/native/jni/src/suggest/core/policy/dictionary_shortcuts_structure_policy.h
+++ b/native/jni/src/dictionary/interface/dictionary_shortcuts_structure_policy.h
diff --git a/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h b/native/jni/src/dictionary/interface/dictionary_structure_with_buffer_policy.h
index e91f07682..ace48491d 100644
--- a/native/jni/src/suggest/core/policy/dictionary_structure_with_buffer_policy.h
+++ b/native/jni/src/dictionary/interface/dictionary_structure_with_buffer_policy.h
@@ -20,16 +20,20 @@
 #include <memory>
 
 #include "defines.h"
-#include "suggest/core/dictionary/property/word_property.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/property/word_attributes.h"
+#include "dictionary/property/word_property.h"
+#include "dictionary/utils/binary_dictionary_shortcut_iterator.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 class DicNode;
 class DicNodeVector;
 class DictionaryHeaderStructurePolicy;
-class DictionaryShortcutsStructurePolicy;
+class MultiBigramMap;
 class NgramListener;
-class PrevWordsInfo;
+class NgramContext;
 class UnigramProperty;
 
 /*
@@ -47,42 +51,45 @@ class DictionaryStructureWithBufferPolicy {
     virtual void createAndGetAllChildDicNodes(const DicNode *const dicNode,
             DicNodeVector *const childDicNodes) const = 0;
 
-    virtual int getCodePointsAndProbabilityAndReturnCodePointCount(
-            const int nodePos, const int maxCodePointCount, int *const outCodePoints,
-            int *const outUnigramProbability) const = 0;
+    virtual int getCodePointsAndReturnCodePointCount(const int wordId, const int maxCodePointCount,
+            int *const outCodePoints) const = 0;
 
-    virtual int getTerminalPtNodePositionOfWord(const int *const inWord,
-            const int length, const bool forceLowerCaseSearch) const = 0;
+    virtual int getWordId(const CodePointArrayView wordCodePoints,
+            const bool forceLowerCaseSearch) const = 0;
 
-    virtual int getProbability(const int unigramProbability,
-            const int bigramProbability) const = 0;
+    virtual const WordAttributes getWordAttributesInContext(const WordIdArrayView prevWordIds,
+            const int wordId, MultiBigramMap *const multiBigramMap) const = 0;
 
-    virtual int getProbabilityOfPtNode(const int *const prevWordsPtNodePos,
-            const int nodePos) const = 0;
+    // TODO: Remove
+    virtual int getProbability(const int unigramProbability, const int bigramProbability) const = 0;
 
-    virtual void iterateNgramEntries(const int *const prevWordsPtNodePos,
+    virtual int getProbabilityOfWord(const WordIdArrayView prevWordIds, const int wordId) const = 0;
+
+    virtual void iterateNgramEntries(const WordIdArrayView prevWordIds,
             NgramListener *const listener) const = 0;
 
-    virtual int getShortcutPositionOfPtNode(const int nodePos) const = 0;
+    virtual BinaryDictionaryShortcutIterator getShortcutIterator(const int wordId) const = 0;
 
     virtual const DictionaryHeaderStructurePolicy *getHeaderStructurePolicy() const = 0;
 
-    virtual const DictionaryShortcutsStructurePolicy *getShortcutsStructurePolicy() const = 0;
-
     // Returns whether the update was success or not.
-    virtual bool addUnigramEntry(const int *const word, const int length,
+    virtual bool addUnigramEntry(const CodePointArrayView wordCodePoints,
             const UnigramProperty *const unigramProperty) = 0;
 
     // Returns whether the update was success or not.
-    virtual bool removeUnigramEntry(const int *const word, const int length) = 0;
+    virtual bool removeUnigramEntry(const CodePointArrayView wordCodePoints) = 0;
+
+    // Returns whether the update was success or not.
+    virtual bool addNgramEntry(const NgramProperty *const ngramProperty) = 0;
 
     // Returns whether the update was success or not.
-    virtual bool addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const BigramProperty *const bigramProperty) = 0;
+    virtual bool removeNgramEntry(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints) = 0;
 
     // Returns whether the update was success or not.
-    virtual bool removeNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const int *const word, const int length) = 0;
+    virtual bool updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints, const bool isValidWord,
+            const HistoricalInfo historicalInfo) = 0;
 
     // Returns whether the flush was success or not.
     virtual bool flush(const char *const filePath) = 0;
@@ -97,9 +104,7 @@ class DictionaryStructureWithBufferPolicy {
     virtual void getProperty(const char *const query, const int queryLength, char *const outResult,
             const int maxResultLength) = 0;
 
-    // Used for testing.
-    virtual const WordProperty getWordProperty(const int *const codePonts,
-            const int codePointCount) const = 0;
+    virtual const WordProperty getWordProperty(const CodePointArrayView wordCodePoints) const = 0;
 
     // Method to iterate all words in the dictionary.
     // The returned token has to be used to get the next word. If token is 0, this method newly
diff --git a/native/jni/src/suggest/core/dictionary/ngram_listener.h b/native/jni/src/dictionary/interface/ngram_listener.h
index 88b88bafb..2eb5e9fd1 100644
--- a/native/jni/src/suggest/core/dictionary/ngram_listener.h
+++ b/native/jni/src/dictionary/interface/ngram_listener.h
@@ -26,7 +26,9 @@ namespace latinime {
  */
 class NgramListener {
  public:
-    virtual void onVisitEntry(const int ngramProbability, const int targetPtNodePos) = 0;
+    // ngramProbability is always 0 for v403 decaying dictionary.
+    // TODO: Remove ngramProbability.
+    virtual void onVisitEntry(const int ngramProbability, const int targetWordId) = 0;
     virtual ~NgramListener() {};
 
  protected:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/historical_info.h b/native/jni/src/dictionary/property/historical_info.h
index 428ca8626..e5ce1ea25 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/historical_info.h
+++ b/native/jni/src/dictionary/property/historical_info.h
@@ -34,10 +34,11 @@ class HistoricalInfo {
         return mTimestamp != NOT_A_TIMESTAMP;
     }
 
-    int getTimeStamp() const {
+    int getTimestamp() const {
         return mTimestamp;
     }
 
+    // TODO: Remove
     int getLevel() const {
         return mLevel;
     }
@@ -47,7 +48,7 @@ class HistoricalInfo {
     }
 
  private:
-    // Copy constructor is public to use this class as a type of return value.
+    // Default copy constructor is used for using in std::vector.
     DISALLOW_ASSIGNMENT_OPERATOR(HistoricalInfo);
 
     const int mTimestamp;
diff --git a/native/jni/src/dictionary/property/ngram_context.cpp b/native/jni/src/dictionary/property/ngram_context.cpp
new file mode 100644
index 000000000..7b9c3eff6
--- /dev/null
+++ b/native/jni/src/dictionary/property/ngram_context.cpp
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/property/ngram_context.h"
+
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "utils/char_utils.h"
+
+namespace latinime {
+
+NgramContext::NgramContext() : mPrevWordCount(0) {}
+
+NgramContext::NgramContext(const NgramContext &ngramContext)
+        : mPrevWordCount(ngramContext.mPrevWordCount) {
+    for (size_t i = 0; i < mPrevWordCount; ++i) {
+        mPrevWordCodePointCount[i] = ngramContext.mPrevWordCodePointCount[i];
+        memmove(mPrevWordCodePoints[i], ngramContext.mPrevWordCodePoints[i],
+                sizeof(mPrevWordCodePoints[i][0]) * mPrevWordCodePointCount[i]);
+        mIsBeginningOfSentence[i] = ngramContext.mIsBeginningOfSentence[i];
+    }
+}
+
+NgramContext::NgramContext(const int prevWordCodePoints[][MAX_WORD_LENGTH],
+        const int *const prevWordCodePointCount, const bool *const isBeginningOfSentence,
+        const size_t prevWordCount)
+        : mPrevWordCount(std::min(NELEMS(mPrevWordCodePoints), prevWordCount)) {
+    clear();
+    for (size_t i = 0; i < mPrevWordCount; ++i) {
+        if (prevWordCodePointCount[i] < 0 || prevWordCodePointCount[i] > MAX_WORD_LENGTH) {
+            continue;
+        }
+        memmove(mPrevWordCodePoints[i], prevWordCodePoints[i],
+                sizeof(mPrevWordCodePoints[i][0]) * prevWordCodePointCount[i]);
+        mPrevWordCodePointCount[i] = prevWordCodePointCount[i];
+        mIsBeginningOfSentence[i] = isBeginningOfSentence[i];
+    }
+}
+
+NgramContext::NgramContext(const int *const prevWordCodePoints, const int prevWordCodePointCount,
+        const bool isBeginningOfSentence) : mPrevWordCount(1) {
+    clear();
+    if (prevWordCodePointCount > MAX_WORD_LENGTH || !prevWordCodePoints) {
+        return;
+    }
+    memmove(mPrevWordCodePoints[0], prevWordCodePoints,
+            sizeof(mPrevWordCodePoints[0][0]) * prevWordCodePointCount);
+    mPrevWordCodePointCount[0] = prevWordCodePointCount;
+    mIsBeginningOfSentence[0] = isBeginningOfSentence;
+}
+
+bool NgramContext::isValid() const {
+    if (mPrevWordCodePointCount[0] > 0) {
+        return true;
+    }
+    if (mIsBeginningOfSentence[0]) {
+        return true;
+    }
+    return false;
+}
+
+const CodePointArrayView NgramContext::getNthPrevWordCodePoints(const size_t n) const {
+    if (n <= 0 || n > mPrevWordCount) {
+        return CodePointArrayView();
+    }
+    return CodePointArrayView(mPrevWordCodePoints[n - 1], mPrevWordCodePointCount[n - 1]);
+}
+
+bool NgramContext::isNthPrevWordBeginningOfSentence(const size_t n) const {
+    if (n <= 0 || n > mPrevWordCount) {
+        return false;
+    }
+    return mIsBeginningOfSentence[n - 1];
+}
+
+/* static */ int NgramContext::getWordId(
+        const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
+        const int *const wordCodePoints, const int wordCodePointCount,
+        const bool isBeginningOfSentence, const bool tryLowerCaseSearch) {
+    if (!dictStructurePolicy || !wordCodePoints || wordCodePointCount > MAX_WORD_LENGTH) {
+        return NOT_A_WORD_ID;
+    }
+    int codePoints[MAX_WORD_LENGTH];
+    int codePointCount = wordCodePointCount;
+    memmove(codePoints, wordCodePoints, sizeof(int) * codePointCount);
+    if (isBeginningOfSentence) {
+        codePointCount = CharUtils::attachBeginningOfSentenceMarker(codePoints, codePointCount,
+                MAX_WORD_LENGTH);
+        if (codePointCount <= 0) {
+            return NOT_A_WORD_ID;
+        }
+    }
+    const CodePointArrayView codePointArrayView(codePoints, codePointCount);
+    const int wordId = dictStructurePolicy->getWordId(codePointArrayView,
+            false /* forceLowerCaseSearch */);
+    if (wordId != NOT_A_WORD_ID || !tryLowerCaseSearch) {
+        // Return the id when when the word was found or doesn't try lower case search.
+        return wordId;
+    }
+    // Check bigrams for lower-cased previous word if original was not found. Useful for
+    // auto-capitalized words like "The [current_word]".
+    return dictStructurePolicy->getWordId(codePointArrayView, true /* forceLowerCaseSearch */);
+}
+
+void NgramContext::clear() {
+    for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
+        mPrevWordCodePointCount[i] = 0;
+        mIsBeginningOfSentence[i] = false;
+    }
+}
+} // namespace latinime
diff --git a/native/jni/src/dictionary/property/ngram_context.h b/native/jni/src/dictionary/property/ngram_context.h
new file mode 100644
index 000000000..9b36199c9
--- /dev/null
+++ b/native/jni/src/dictionary/property/ngram_context.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_NGRAM_CONTEXT_H
+#define LATINIME_NGRAM_CONTEXT_H
+
+#include <array>
+
+#include "defines.h"
+#include "utils/int_array_view.h"
+
+namespace latinime {
+
+class DictionaryStructureWithBufferPolicy;
+
+class NgramContext {
+ public:
+    // No prev word information.
+    NgramContext();
+    // Copy constructor to use this class with std::vector and use this class as a return value.
+    NgramContext(const NgramContext &ngramContext);
+    // Construct from previous words.
+    NgramContext(const int prevWordCodePoints[][MAX_WORD_LENGTH],
+            const int *const prevWordCodePointCount, const bool *const isBeginningOfSentence,
+            const size_t prevWordCount);
+    // Construct from a previous word.
+    NgramContext(const int *const prevWordCodePoints, const int prevWordCodePointCount,
+            const bool isBeginningOfSentence);
+
+    size_t getPrevWordCount() const {
+        return mPrevWordCount;
+    }
+    bool isValid() const;
+
+    template<size_t N>
+    const WordIdArrayView getPrevWordIds(
+            const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
+            WordIdArray<N> *const prevWordIdBuffer, const bool tryLowerCaseSearch) const {
+        for (size_t i = 0; i < std::min(mPrevWordCount, N); ++i) {
+            prevWordIdBuffer->at(i) = getWordId(dictStructurePolicy, mPrevWordCodePoints[i],
+                    mPrevWordCodePointCount[i], mIsBeginningOfSentence[i], tryLowerCaseSearch);
+        }
+        return WordIdArrayView::fromArray(*prevWordIdBuffer).limit(mPrevWordCount);
+    }
+
+    // n is 1-indexed.
+    const CodePointArrayView getNthPrevWordCodePoints(const size_t n) const;
+    // n is 1-indexed.
+    bool isNthPrevWordBeginningOfSentence(const size_t n) const;
+
+ private:
+    DISALLOW_ASSIGNMENT_OPERATOR(NgramContext);
+
+    static int getWordId(const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
+            const int *const wordCodePoints, const int wordCodePointCount,
+            const bool isBeginningOfSentence, const bool tryLowerCaseSearch);
+    void clear();
+
+    const size_t mPrevWordCount;
+    int mPrevWordCodePoints[MAX_PREV_WORD_COUNT_FOR_N_GRAM][MAX_WORD_LENGTH];
+    int mPrevWordCodePointCount[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    bool mIsBeginningOfSentence[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+};
+} // namespace latinime
+#endif // LATINIME_NGRAM_CONTEXT_H
diff --git a/native/jni/src/dictionary/property/ngram_property.h b/native/jni/src/dictionary/property/ngram_property.h
new file mode 100644
index 000000000..5f259ec59
--- /dev/null
+++ b/native/jni/src/dictionary/property/ngram_property.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_NGRAM_PROPERTY_H
+#define LATINIME_NGRAM_PROPERTY_H
+
+#include <vector>
+
+#include "defines.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/property/ngram_context.h"
+
+namespace latinime {
+
+class NgramProperty {
+ public:
+    NgramProperty(const NgramContext &ngramContext, const std::vector<int> &&targetCodePoints,
+            const int probability, const HistoricalInfo historicalInfo)
+            : mNgramContext(ngramContext), mTargetCodePoints(std::move(targetCodePoints)),
+              mProbability(probability), mHistoricalInfo(historicalInfo) {}
+
+    const NgramContext *getNgramContext() const {
+        return &mNgramContext;
+    }
+
+    const std::vector<int> *getTargetCodePoints() const {
+        return &mTargetCodePoints;
+    }
+
+    int getProbability() const {
+        return mProbability;
+    }
+
+    const HistoricalInfo getHistoricalInfo() const {
+        return mHistoricalInfo;
+    }
+
+ private:
+    // Default copy constructor is used for using in std::vector.
+    DISALLOW_DEFAULT_CONSTRUCTOR(NgramProperty);
+    DISALLOW_ASSIGNMENT_OPERATOR(NgramProperty);
+
+    const NgramContext mNgramContext;
+    const std::vector<int> mTargetCodePoints;
+    const int mProbability;
+    const HistoricalInfo mHistoricalInfo;
+};
+} // namespace latinime
+#endif // LATINIME_NGRAM_PROPERTY_H
diff --git a/native/jni/src/dictionary/property/unigram_property.h b/native/jni/src/dictionary/property/unigram_property.h
new file mode 100644
index 000000000..92f61b85d
--- /dev/null
+++ b/native/jni/src/dictionary/property/unigram_property.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_UNIGRAM_PROPERTY_H
+#define LATINIME_UNIGRAM_PROPERTY_H
+
+#include <vector>
+
+#include "defines.h"
+#include "dictionary/property/historical_info.h"
+
+namespace latinime {
+
+class UnigramProperty {
+ public:
+    class ShortcutProperty {
+     public:
+        ShortcutProperty(const std::vector<int> &&targetCodePoints, const int probability)
+                : mTargetCodePoints(std::move(targetCodePoints)),
+                  mProbability(probability) {}
+
+        const std::vector<int> *getTargetCodePoints() const {
+            return &mTargetCodePoints;
+        }
+
+        int getProbability() const {
+            return mProbability;
+        }
+
+     private:
+        // Default copy constructor is used for using in std::vector.
+        DISALLOW_DEFAULT_CONSTRUCTOR(ShortcutProperty);
+
+        const std::vector<int> mTargetCodePoints;
+        const int mProbability;
+    };
+
+    UnigramProperty()
+            : mRepresentsBeginningOfSentence(false), mIsNotAWord(false),
+              mIsBlacklisted(false), mIsPossiblyOffensive(false), mProbability(NOT_A_PROBABILITY),
+              mHistoricalInfo(), mShortcuts() {}
+
+    // In contexts which do not support the Blacklisted flag (v2, v4<403)
+    UnigramProperty(const bool representsBeginningOfSentence, const bool isNotAWord,
+            const bool isPossiblyOffensive, const int probability,
+            const HistoricalInfo historicalInfo, const std::vector<ShortcutProperty> &&shortcuts)
+            : mRepresentsBeginningOfSentence(representsBeginningOfSentence),
+              mIsNotAWord(isNotAWord), mIsBlacklisted(false),
+              mIsPossiblyOffensive(isPossiblyOffensive), mProbability(probability),
+              mHistoricalInfo(historicalInfo), mShortcuts(std::move(shortcuts)) {}
+
+    // Without shortcuts, in contexts which do not support the Blacklisted flag (v2, v4<403)
+    UnigramProperty(const bool representsBeginningOfSentence, const bool isNotAWord,
+            const bool isPossiblyOffensive, const int probability,
+            const HistoricalInfo historicalInfo)
+            : mRepresentsBeginningOfSentence(representsBeginningOfSentence),
+              mIsNotAWord(isNotAWord), mIsBlacklisted(false),
+              mIsPossiblyOffensive(isPossiblyOffensive), mProbability(probability),
+              mHistoricalInfo(historicalInfo), mShortcuts() {}
+
+    // In contexts which DO support the Blacklisted flag (v403)
+    UnigramProperty(const bool representsBeginningOfSentence, const bool isNotAWord,
+            const bool isBlacklisted, const bool isPossiblyOffensive, const int probability,
+            const HistoricalInfo historicalInfo, const std::vector<ShortcutProperty> &&shortcuts)
+            : mRepresentsBeginningOfSentence(representsBeginningOfSentence),
+              mIsNotAWord(isNotAWord), mIsBlacklisted(isBlacklisted),
+              mIsPossiblyOffensive(isPossiblyOffensive), mProbability(probability),
+              mHistoricalInfo(historicalInfo), mShortcuts(std::move(shortcuts)) {}
+
+    // Without shortcuts, in contexts which DO support the Blacklisted flag (v403)
+    UnigramProperty(const bool representsBeginningOfSentence, const bool isNotAWord,
+            const bool isBlacklisted, const bool isPossiblyOffensive, const int probability,
+            const HistoricalInfo historicalInfo)
+            : mRepresentsBeginningOfSentence(representsBeginningOfSentence),
+              mIsNotAWord(isNotAWord), mIsBlacklisted(isBlacklisted),
+              mIsPossiblyOffensive(isPossiblyOffensive), mProbability(probability),
+              mHistoricalInfo(historicalInfo), mShortcuts() {}
+
+    bool representsBeginningOfSentence() const {
+        return mRepresentsBeginningOfSentence;
+    }
+
+    bool isNotAWord() const {
+        return mIsNotAWord;
+    }
+
+    bool isPossiblyOffensive() const {
+        return mIsPossiblyOffensive;
+    }
+
+    bool isBlacklisted() const {
+        return mIsBlacklisted;
+    }
+
+    bool hasShortcuts() const {
+        return !mShortcuts.empty();
+    }
+
+    int getProbability() const {
+        return mProbability;
+    }
+
+    const HistoricalInfo getHistoricalInfo() const {
+        return mHistoricalInfo;
+    }
+
+    const std::vector<ShortcutProperty> &getShortcuts() const {
+        return mShortcuts;
+    }
+
+ private:
+    // Default copy constructor is used for using as a return value.
+    DISALLOW_ASSIGNMENT_OPERATOR(UnigramProperty);
+
+    const bool mRepresentsBeginningOfSentence;
+    const bool mIsNotAWord;
+    const bool mIsBlacklisted;
+    const bool mIsPossiblyOffensive;
+    const int mProbability;
+    const HistoricalInfo mHistoricalInfo;
+    const std::vector<ShortcutProperty> mShortcuts;
+};
+} // namespace latinime
+#endif // LATINIME_UNIGRAM_PROPERTY_H
diff --git a/native/jni/src/dictionary/property/word_attributes.h b/native/jni/src/dictionary/property/word_attributes.h
new file mode 100644
index 000000000..5351e7d7d
--- /dev/null
+++ b/native/jni/src/dictionary/property/word_attributes.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_WORD_ATTRIBUTES_H
+#define LATINIME_WORD_ATTRIBUTES_H
+
+#include "defines.h"
+
+class WordAttributes {
+ public:
+    // Invalid word attributes.
+    WordAttributes()
+            : mProbability(NOT_A_PROBABILITY), mIsBlacklisted(false), mIsNotAWord(false),
+              mIsPossiblyOffensive(false) {}
+
+    WordAttributes(const int probability, const bool isBlacklisted, const bool isNotAWord,
+            const bool isPossiblyOffensive)
+            : mProbability(probability), mIsBlacklisted(isBlacklisted), mIsNotAWord(isNotAWord),
+              mIsPossiblyOffensive(isPossiblyOffensive) {}
+
+    int getProbability() const {
+        return mProbability;
+    }
+
+    bool isBlacklisted() const {
+        return mIsBlacklisted;
+    }
+
+    bool isNotAWord() const {
+        return mIsNotAWord;
+    }
+
+    // Whether or not a word is possibly offensive.
+    // * Static dictionaries <v202, as well as dynamic dictionaries <v403, will set this based on
+    //   whether or not the probability of the word is zero.
+    // * Static dictionaries >=v203 will set this based on the IS_POSSIBLY_OFFENSIVE PtNode flag.
+    // * Dynamic dictionaries >=v403 will set this based on the IS_POSSIBLY_OFFENSIVE language model
+    //   flag (the PtNode flag IS_BLACKLISTED is ignored and kept as zero)
+    //
+    // See the ::getWordAttributes function for each of these dictionary policies for more details.
+    bool isPossiblyOffensive() const {
+        return mIsPossiblyOffensive;
+    }
+
+ private:
+    DISALLOW_ASSIGNMENT_OPERATOR(WordAttributes);
+
+    int mProbability;
+    bool mIsBlacklisted;
+    bool mIsNotAWord;
+    bool mIsPossiblyOffensive;
+};
+
+ // namespace
+#endif /* LATINIME_WORD_ATTRIBUTES_H */
diff --git a/native/jni/src/suggest/core/dictionary/property/word_property.h b/native/jni/src/dictionary/property/word_property.h
index aa3e0b68a..3028e020a 100644
--- a/native/jni/src/suggest/core/dictionary/property/word_property.h
+++ b/native/jni/src/dictionary/property/word_property.h
@@ -20,9 +20,9 @@
 #include <vector>
 
 #include "defines.h"
-#include "jni.h"
-#include "suggest/core/dictionary/property/bigram_property.h"
-#include "suggest/core/dictionary/property/unigram_property.h"
+#include "dictionary/property/ngram_property.h"
+#include "dictionary/property/unigram_property.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -31,23 +31,23 @@ class WordProperty {
  public:
     // Default constructor is used to create an instance that indicates an invalid word.
     WordProperty()
-            : mCodePoints(), mUnigramProperty(), mBigrams() {}
+            : mCodePoints(), mUnigramProperty(), mNgrams() {}
 
-    WordProperty(const std::vector<int> *const codePoints,
-            const UnigramProperty *const unigramProperty,
-            const std::vector<BigramProperty> *const bigrams)
-            : mCodePoints(*codePoints), mUnigramProperty(*unigramProperty), mBigrams(*bigrams) {}
+    WordProperty(const std::vector<int> &&codePoints, const UnigramProperty &unigramProperty,
+            const std::vector<NgramProperty> &ngrams)
+            : mCodePoints(std::move(codePoints)), mUnigramProperty(unigramProperty),
+              mNgrams(ngrams) {}
 
-    void outputProperties(JNIEnv *const env, jintArray outCodePoints, jbooleanArray outFlags,
-            jintArray outProbabilityInfo, jobject outBigramTargets, jobject outBigramProbabilities,
-            jobject outShortcutTargets, jobject outShortcutProbabilities) const;
+    const CodePointArrayView getCodePoints() const {
+        return CodePointArrayView(mCodePoints);
+    }
 
-    const UnigramProperty *getUnigramProperty() const {
-        return &mUnigramProperty;
+    const UnigramProperty &getUnigramProperty() const {
+        return mUnigramProperty;
     }
 
-    const std::vector<BigramProperty> *getBigramProperties() const {
-        return &mBigrams;
+    const std::vector<NgramProperty> &getNgramProperties() const {
+        return mNgrams;
     }
 
  private:
@@ -56,7 +56,7 @@ class WordProperty {
 
     const std::vector<int> mCodePoints;
     const UnigramProperty mUnigramProperty;
-    const std::vector<BigramProperty> mBigrams;
+    const std::vector<NgramProperty> mNgrams;
 };
 } // namespace latinime
 #endif // LATINIME_WORD_PROPERTY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/Readme.txt b/native/jni/src/dictionary/structure/backward/v402/Readme.txt
index 9e29e836c..9e29e836c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/Readme.txt
+++ b/native/jni/src/dictionary/structure/backward/v402/Readme.txt
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.cpp b/native/jni/src/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.cpp
index 3e8e059f2..60749bce6 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.cpp
@@ -19,18 +19,18 @@
  * Do not edit this file other than updating policy's interface.
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp
+ *   dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
+#include "dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
 
-#include "suggest/core/dictionary/property/bigram_property.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/property/ngram_property.h"
+#include "dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
+#include "dictionary/structure/backward/v402/content/bigram_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 namespace backward {
@@ -60,7 +60,7 @@ void Ver4BigramListPolicy::getNextBigram(int *const outBigramPos, int *const out
 }
 
 bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTargetTerminalId,
-        const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) {
+        const NgramProperty *const ngramProperty, bool *const outAddedNewEntry) {
     // 1. The word has no bigrams yet.
     // 2. The word has bigrams, and there is the target in the list.
     // 3. The word has bigrams, and there is an invalid entry that can be reclaimed.
@@ -79,7 +79,7 @@ bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTarget
         const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
                 newTargetTerminalId);
         const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(&newBigramEntry,
-                bigramProperty);
+                ngramProperty);
         // Write an entry.
         const int writingPos =  mBigramDictContent->getBigramListHeadPos(terminalId);
         if (!mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, writingPos)) {
@@ -112,7 +112,7 @@ bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTarget
         const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
                 newTargetTerminalId);
         const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-                &newBigramEntry, bigramProperty);
+                &newBigramEntry, ngramProperty);
         if (!mBigramDictContent->writeBigramEntryAtTail(&bigramEntryToWrite)) {
             return false;
         }
@@ -138,7 +138,7 @@ bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTarget
     const BigramEntry updatedBigramEntry =
             originalBigramEntry.updateTargetTerminalIdAndGetEntry(newTargetTerminalId);
     const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-            &updatedBigramEntry, bigramProperty);
+            &updatedBigramEntry, ngramProperty);
     return mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, entryPosToUpdate);
 }
 
@@ -264,18 +264,17 @@ int Ver4BigramListPolicy::getEntryPosToUpdate(const int targetTerminalIdToFind,
 
 const BigramEntry Ver4BigramListPolicy::createUpdatedBigramEntryFrom(
         const BigramEntry *const originalBigramEntry,
-        const BigramProperty *const bigramProperty) const {
+        const NgramProperty *const ngramProperty) const {
     // TODO: Consolidate historical info and probability.
     if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
-        const HistoricalInfo historicalInfoForUpdate(bigramProperty->getTimestamp(),
-                bigramProperty->getLevel(), bigramProperty->getCount());
+        const HistoricalInfo &historicalInfoForUpdate = ngramProperty->getHistoricalInfo();
         const HistoricalInfo updatedHistoricalInfo =
                 ForgettingCurveUtils::createUpdatedHistoricalInfo(
-                        originalBigramEntry->getHistoricalInfo(), bigramProperty->getProbability(),
+                        originalBigramEntry->getHistoricalInfo(), ngramProperty->getProbability(),
                         &historicalInfoForUpdate, mHeaderPolicy);
         return originalBigramEntry->updateHistoricalInfoAndGetEntry(&updatedHistoricalInfo);
     } else {
-        return originalBigramEntry->updateProbabilityAndGetEntry(bigramProperty->getProbability());
+        return originalBigramEntry->updateProbabilityAndGetEntry(ngramProperty->getProbability());
     }
 }
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h b/native/jni/src/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h
index 50a4c9743..58c88ce8a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h
+++ b/native/jni/src/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h
@@ -26,8 +26,8 @@
 #define LATINIME_BACKWARD_V402_VER4_BIGRAM_LIST_POLICY_H
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_entry.h"
+#include "dictionary/interface/dictionary_bigrams_structure_policy.h"
+#include "dictionary/structure/backward/v402/content/bigram_entry.h"
 
 namespace latinime {
 namespace backward {
@@ -36,7 +36,7 @@ namespace v402 {
 class BigramDictContent;
 } // namespace v402
 } // namespace backward
-class BigramProperty;
+class NgramProperty;
 namespace backward {
 namespace v402 {
 } // namespace v402
@@ -64,7 +64,7 @@ class Ver4BigramListPolicy : public DictionaryBigramsStructurePolicy {
     }
 
     bool addNewEntry(const int terminalId, const int newTargetTerminalId,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
+            const NgramProperty *const ngramProperty, bool *const outAddedNewEntry);
 
     bool removeEntry(const int terminalId, const int targetTerminalId);
 
@@ -80,7 +80,7 @@ class Ver4BigramListPolicy : public DictionaryBigramsStructurePolicy {
             int *const outTailEntryPos) const;
 
     const BigramEntry createUpdatedBigramEntryFrom(const BigramEntry *const originalBigramEntry,
-            const BigramProperty *const bigramProperty) const;
+            const NgramProperty *const ngramProperty) const;
 
     bool updateHasNextFlag(const bool hasNext, const int bigramEntryPos);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.cpp b/native/jni/src/dictionary/structure/backward/v402/content/bigram_dict_content.cpp
index e2dd93c5e..7fa85dec2 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/content/bigram_dict_content.cpp
@@ -18,12 +18,12 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.cpp
+ *   dictionary/structure/v4/content/bigram_dict_content.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.h"
+#include "dictionary/structure/backward/v402/content/bigram_dict_content.h"
 
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
@@ -65,6 +65,8 @@ const BigramEntry BigramDictContent::getBigramEntryAndAdvancePosition(
             (encodedTargetTerminalId == Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID) ?
                     Ver4DictConstants::NOT_A_TERMINAL_ID : encodedTargetTerminalId;
     if (mHasHistoricalInfo) {
+        // Hack for better migration.
+        count += level;
         const HistoricalInfo historicalInfo(timestamp, level, count);
         return BigramEntry(hasNext, probability, &historicalInfo, targetTerminalId);
     } else {
@@ -83,10 +85,10 @@ bool BigramDictContent::writeBigramEntryAndAdvancePosition(
     }
     if (mHasHistoricalInfo) {
         const HistoricalInfo *const historicalInfo = bigramEntryToWrite->getHistoricalInfo();
-        if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getTimeStamp(),
+        if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getTimestamp(),
                 Ver4DictConstants::TIME_STAMP_FIELD_SIZE, entryWritingPos)) {
             AKLOGE("Cannot write bigram timestamps. pos: %d, timestamp: %d", *entryWritingPos,
-                    historicalInfo->getTimeStamp());
+                    historicalInfo->getTimestamp());
             return false;
         }
         if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getLevel(),
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/bigram_dict_content.h
index b554e5676..14f334a12 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/bigram_dict_content.h
@@ -18,17 +18,17 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h
+ *   dictionary/structure/v4/content/bigram_dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_BIGRAM_DICT_CONTENT_H
 #define LATINIME_BACKWARD_V402_BIGRAM_DICT_CONTENT_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_entry.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/content/bigram_entry.h"
+#include "dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_entry.h b/native/jni/src/dictionary/structure/backward/v402/content/bigram_entry.h
index 40968b4d8..36ad855ee 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_entry.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/bigram_entry.h
@@ -18,15 +18,15 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h
+ *   dictionary/structure/v4/content/bigram_entry.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_BIGRAM_ENTRY_H
 #define LATINIME_BACKWARD_V402_BIGRAM_ENTRY_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/dict_content.h
index 0f2f25534..d3b84fa04 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/dict_content.h
@@ -18,7 +18,7 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/dict_content.h
+ *   dictionary/structure/v4/content/dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_DICT_CONTENT_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.cpp b/native/jni/src/dictionary/structure/backward/v402/content/probability_dict_content.cpp
index c671647d4..b167f0ab2 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/content/probability_dict_content.cpp
@@ -18,15 +18,15 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.cpp
+ *   dictionary/structure/v4/content/probability_dict_content.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.h"
+#include "dictionary/structure/backward/v402/content/probability_dict_content.h"
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/backward/v402/content/probability_entry.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
@@ -50,7 +50,8 @@ const ProbabilityEntry ProbabilityDictContent::getProbabilityEntry(const int ter
                 Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, &entryPos);
         const int count = buffer->readUintAndAdvancePosition(
                 Ver4DictConstants::WORD_COUNT_FIELD_SIZE, &entryPos);
-        const HistoricalInfo historicalInfo(timestamp, level, count);
+        // Hack for better migration.
+        const HistoricalInfo historicalInfo(timestamp, level, count + level);
         return ProbabilityEntry(flags, probability, &historicalInfo);
     } else {
         return ProbabilityEntry(flags, probability);
@@ -74,8 +75,8 @@ bool ProbabilityDictContent::setProbabilityEntry(const int terminalId,
                 return false;
             }
             writingPos += getEntrySize();
-            mSize++;
         }
+        mSize = terminalId + 1;
     }
     return writeEntry(probabilityEntry, entryPos);
 }
@@ -100,7 +101,6 @@ bool ProbabilityDictContent::flushToFile(const char *const dictPath) const {
 bool ProbabilityDictContent::runGC(
         const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
         const ProbabilityDictContent *const originalProbabilityDictContent) {
-    mSize = 0;
     for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
             it != terminalIdMap->end(); ++it) {
         const ProbabilityEntry probabilityEntry =
@@ -109,7 +109,6 @@ bool ProbabilityDictContent::runGC(
             AKLOGE("Cannot set probability entry in runGC. terminalId: %d", it->second);
             return false;
         }
-        mSize++;
     }
     return true;
 }
@@ -147,7 +146,7 @@ bool ProbabilityDictContent::writeEntry(const ProbabilityEntry *const probabilit
     }
     if (mHasHistoricalInfo) {
         const HistoricalInfo *const historicalInfo = probabilityEntry->getHistoricalInfo();
-        if (!bufferToWrite->writeUintAndAdvancePosition(historicalInfo->getTimeStamp(),
+        if (!bufferToWrite->writeUintAndAdvancePosition(historicalInfo->getTimestamp(),
                 Ver4DictConstants::TIME_STAMP_FIELD_SIZE, &writingPos)) {
             AKLOGE("Cannot write timestamp in probability dict content. pos: %d", writingPos);
             return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/probability_dict_content.h
index 3734797d4..464b29f3f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/probability_dict_content.h
@@ -18,17 +18,17 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h
+ *   dictionary/structure/v4/content/probability_dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_PROBABILITY_DICT_CONTENT_H
 #define LATINIME_BACKWARD_V402_PROBABILITY_DICT_CONTENT_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/single_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/backward/v402/content/single_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h b/native/jni/src/dictionary/structure/backward/v402/content/probability_entry.h
index 8ccfa33dc..94e36bf51 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/probability_entry.h
@@ -18,15 +18,15 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h
+ *   dictionary/structure/v4/content/probability_entry.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_PROBABILITY_ENTRY_H
 #define LATINIME_BACKWARD_V402_PROBABILITY_ENTRY_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.cpp b/native/jni/src/dictionary/structure/backward/v402/content/shortcut_dict_content.cpp
index 56bc8b98d..e538a02a1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/content/shortcut_dict_content.cpp
@@ -18,12 +18,12 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.cpp
+ *   dictionary/structure/v4/content/shortcut_dict_content.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.h"
+#include "dictionary/structure/backward/v402/content/shortcut_dict_content.h"
 
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/shortcut_dict_content.h
index 179cec5bb..3b725e896 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/shortcut_dict_content.h
@@ -18,16 +18,16 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h
+ *   dictionary/structure/v4/content/shortcut_dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_SHORTCUT_DICT_CONTENT_H
 #define LATINIME_BACKWARD_V402_SHORTCUT_DICT_CONTENT_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/single_dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/single_dict_content.h
index 49f446814..89df2a1e0 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/single_dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/single_dict_content.h
@@ -18,18 +18,18 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
+ *   dictionary/structure/v4/content/single_dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_SINGLE_DICT_CONTENT_H
 #define LATINIME_BACKWARD_V402_SINGLE_DICT_CONTENT_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/structure/backward/v402/content/dict_content.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/mmapped_buffer.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.cpp b/native/jni/src/dictionary/structure/backward/v402/content/sparse_table_dict_content.cpp
index 7c9b4967a..280f0f85a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/content/sparse_table_dict_content.cpp
@@ -18,10 +18,10 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
+ *   dictionary/structure/v4/content/sparse_table_dict_content.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
+#include "dictionary/structure/backward/v402/content/sparse_table_dict_content.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.h b/native/jni/src/dictionary/structure/backward/v402/content/sparse_table_dict_content.h
index 3c626df11..4b5af87ad 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/sparse_table_dict_content.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/sparse_table_dict_content.h
@@ -18,19 +18,19 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h
+ *   dictionary/structure/v4/content/sparse_table_dict_content.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_SPARSE_TABLE_DICT_CONTENT_H
 #define LATINIME_BACKWARD_V402_SPARSE_TABLE_DICT_CONTENT_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/sparse_table.h"
+#include "dictionary/structure/backward/v402/content/dict_content.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/mmapped_buffer.h"
+#include "dictionary/utils/sparse_table.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.cpp b/native/jni/src/dictionary/structure/backward/v402/content/terminal_position_lookup_table.cpp
index a9f841779..30b72bbd1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/content/terminal_position_lookup_table.cpp
@@ -18,13 +18,13 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
+ *   dictionary/structure/v4/content/terminal_position_lookup_table.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h b/native/jni/src/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h
index eadfe0faa..641c7496f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h
+++ b/native/jni/src/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h
@@ -18,7 +18,7 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
+ *   dictionary/structure/v4/content/terminal_position_lookup_table.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_TERMINAL_POSITION_LOOKUP_TABLE_H
@@ -27,8 +27,8 @@
 #include <unordered_map>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/single_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/content/single_dict_content.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h b/native/jni/src/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h
index 941fda748..8cda8c5cf 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h
+++ b/native/jni/src/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h
@@ -19,17 +19,17 @@
  * Do not edit this file other than updating policy's interface.
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
+ *   dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_SHORTCUT_LIST_POLICY_H
 #define LATINIME_BACKWARD_V402_VER4_SHORTCUT_LIST_POLICY_H
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/interface/dictionary_shortcuts_structure_policy.h"
+#include "dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "dictionary/structure/backward/v402/content/shortcut_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_buffers.cpp
index 3dfbd1c94..4a9704f4d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_buffers.cpp
@@ -18,18 +18,18 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+ *   dictionary/structure/v4/ver4_dict_buffers.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
 
 #include <cerrno>
 #include <cstring>
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/file_utils.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_buffers.h
index e775be52e..0d09fee9a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_buffers.h
@@ -18,7 +18,7 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
+ *   dictionary/structure/v4/ver4_dict_buffers.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_DICT_BUFFER_H
@@ -27,14 +27,14 @@
 #include <memory>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/bigram_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/shortcut_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/backward/v402/content/bigram_dict_content.h"
+#include "dictionary/structure/backward/v402/content/probability_dict_content.h"
+#include "dictionary/structure/backward/v402/content/shortcut_dict_content.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/mmapped_buffer.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_constants.cpp
index 81d85f495..2948d0716 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_constants.cpp
@@ -18,10 +18,10 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
+ *   dictionary/structure/v4/ver4_dict_constants.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_constants.h
index 88ebd6a75..15581d852 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_dict_constants.h
@@ -18,7 +18,7 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
+ *   dictionary/structure/v4/ver4_dict_constants.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_DICT_CONSTANTS_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.cpp
index 82399f190..871ef7aaf 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.cpp
@@ -18,18 +18,19 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
+ *   dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/backward/v402/content/probability_dict_content.h"
+#include "dictionary/structure/backward/v402/content/probability_entry.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 namespace backward {
@@ -59,8 +60,8 @@ const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProce
     const int parentPos =
             DynamicPtReadingUtils::getParentPtNodePos(parentPosOffset, headPos);
     int codePoints[MAX_WORD_LENGTH];
-    const int codePonitCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
-            dictBuf, flags, MAX_WORD_LENGTH, codePoints, &pos);
+    const int codePointCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
+            dictBuf, flags, MAX_WORD_LENGTH, mHeaderPolicy->getCodePointTable(), codePoints, &pos);
     int terminalIdFieldPos = NOT_A_DICT_POS;
     int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
     int probability = NOT_A_PROBABILITY;
@@ -98,7 +99,7 @@ const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProce
         // The destination position is stored at the same place as the parent position.
         return fetchPtNodeInfoFromBufferAndProcessMovedPtNode(parentPos, newSiblingNodePos);
     } else {
-        return PtNodeParams(headPos, flags, parentPos, codePonitCount, codePoints,
+        return PtNodeParams(headPos, flags, parentPos, codePointCount, codePoints,
                 terminalIdFieldPos, terminalId, probability, childrenPosFieldPos, childrenPos,
                 newSiblingNodePos);
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h
index 1999a51a6..367d6f9f8 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h
@@ -18,15 +18,15 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h
+ *   dictionary/structure/v4/ver4_patricia_trie_node_reader.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_NODE_READER_H
 #define LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_NODE_READER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_reader.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.cpp
index 278f2b199..e3ab5ec20 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.cpp
@@ -18,23 +18,23 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
+ *   dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
 
-#include "suggest/core/dictionary/property/unigram_property.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
+#include "dictionary/structure/backward/v402/content/probability_entry.h"
+#include "dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 namespace backward {
@@ -232,10 +232,10 @@ bool Ver4PatriciaTrieNodeWriter::writeNewTerminalPtNodeAndAdvancePosition(
 }
 
 bool Ver4PatriciaTrieNodeWriter::addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
-        const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) {
-    if (!mBigramPolicy->addNewEntry(prevWordIds[0], wordId, bigramProperty, outAddedNewEntry)) {
-        AKLOGE("Cannot add new bigram entry. terminalId: %d, targetTerminalId: %d",
-                sourcePtNodeParams->getTerminalId(), targetPtNodeParam->getTerminalId());
+        const NgramProperty *const ngramProperty, bool *const outAddedNewEntry) {
+    if (!mBigramPolicy->addNewEntry(prevWordIds[0], wordId, ngramProperty, outAddedNewEntry)) {
+        AKLOGE("Cannot add new bigram entry. prevWordId: %d, wordId: %d",
+                prevWordIds[0], wordId);
         return false;
     }
     const int ptNodePos =
@@ -245,7 +245,7 @@ bool Ver4PatriciaTrieNodeWriter::addNgramEntry(const WordIdArrayView prevWordIds
     if (!sourcePtNodeParams.hasBigrams()) {
         // Update has bigrams flag.
         return updatePtNodeFlags(sourcePtNodeParams.getHeadPos(),
-                sourcePtNodeParams.isBlacklisted(), sourcePtNodeParams.isNotAWord(),
+                sourcePtNodeParams.isPossiblyOffensive(), sourcePtNodeParams.isNotAWord(),
                 sourcePtNodeParams.isTerminal(), sourcePtNodeParams.hasShortcutTargets(),
                 true /* hasBigrams */,
                 sourcePtNodeParams.getCodePointCount() > 1 /* hasMultipleChars */);
@@ -310,13 +310,13 @@ bool Ver4PatriciaTrieNodeWriter::addShortcutTarget(const PtNodeParams *const ptN
         const int shortcutProbability) {
     if (!mShortcutPolicy->addNewShortcut(ptNodeParams->getTerminalId(),
             targetCodePoints, targetCodePointCount, shortcutProbability)) {
-        AKLOGE("Cannot add new shortuct entry. terminalId: %d", ptNodeParams->getTerminalId());
+        AKLOGE("Cannot add new shortcut entry. terminalId: %d", ptNodeParams->getTerminalId());
         return false;
     }
     if (!ptNodeParams->hasShortcutTargets()) {
         // Update has shortcut targets flag.
         return updatePtNodeFlags(ptNodeParams->getHeadPos(),
-                ptNodeParams->isBlacklisted(), ptNodeParams->isNotAWord(),
+                ptNodeParams->isPossiblyOffensive(), ptNodeParams->isNotAWord(),
                 ptNodeParams->isTerminal(), true /* hasShortcutTargets */,
                 ptNodeParams->hasBigrams(),
                 ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
@@ -330,7 +330,7 @@ bool Ver4PatriciaTrieNodeWriter::updatePtNodeHasBigramsAndShortcutTargetsFlags(
             ptNodeParams->getTerminalId()) != NOT_A_DICT_POS;
     const bool hasShortcutTargets = mBuffers->getShortcutDictContent()->getShortcutListHeadPos(
             ptNodeParams->getTerminalId()) != NOT_A_DICT_POS;
-    return updatePtNodeFlags(ptNodeParams->getHeadPos(), ptNodeParams->isBlacklisted(),
+    return updatePtNodeFlags(ptNodeParams->getHeadPos(), ptNodeParams->isPossiblyOffensive(),
             ptNodeParams->isNotAWord(), ptNodeParams->isTerminal(), hasShortcutTargets,
             hasBigrams, ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
 }
@@ -386,8 +386,9 @@ bool Ver4PatriciaTrieNodeWriter::writePtNodeAndGetTerminalIdAndAdvancePosition(
             ptNodeParams->getChildrenPos(), ptNodeWritingPos)) {
         return false;
     }
-    return updatePtNodeFlags(nodePos, ptNodeParams->isBlacklisted(), ptNodeParams->isNotAWord(),
-            isTerminal, ptNodeParams->hasShortcutTargets(), ptNodeParams->hasBigrams(),
+    return updatePtNodeFlags(nodePos, ptNodeParams->isPossiblyOffensive(),
+            ptNodeParams->isNotAWord(), isTerminal, ptNodeParams->hasShortcutTargets(),
+            ptNodeParams->hasBigrams(),
             ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
 }
 
@@ -396,8 +397,7 @@ const ProbabilityEntry Ver4PatriciaTrieNodeWriter::createUpdatedEntryFrom(
         const UnigramProperty *const unigramProperty) const {
     // TODO: Consolidate historical info and probability.
     if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
-        const HistoricalInfo historicalInfoForUpdate(unigramProperty->getTimestamp(),
-                unigramProperty->getLevel(), unigramProperty->getCount());
+        const HistoricalInfo &historicalInfoForUpdate = unigramProperty->getHistoricalInfo();
         const HistoricalInfo updatedHistoricalInfo =
                 ForgettingCurveUtils::createUpdatedHistoricalInfo(
                         originalProbabilityEntry->getHistoricalInfo(),
@@ -425,6 +425,18 @@ bool Ver4PatriciaTrieNodeWriter::updatePtNodeFlags(const int ptNodePos,
     return true;
 }
 
+bool Ver4PatriciaTrieNodeWriter::suppressUnigramEntry(const PtNodeParams *const ptNodeParams) {
+    if (!mHeaderPolicy->hasHistoricalInfoOfWords()) {
+        // Require historical info to suppress unigram entry.
+        return false;
+    }
+    const HistoricalInfo suppressedHistorycalInfo(0 /* timestamp */, 0 /* level */, 0 /* count */);
+    const ProbabilityEntry probabilityEntryToWrite =
+            ProbabilityEntry().createEntryWithUpdatedHistoricalInfo(&suppressedHistorycalInfo);
+    return mBuffers->getMutableProbabilityDictContent()->setProbabilityEntry(
+            ptNodeParams->getTerminalId(), &probabilityEntryToWrite);
+}
+
 } // namespace v402
 } // namespace backward
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h
index d49d9a666..db3cea174 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h
@@ -18,17 +18,17 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
+ *   dictionary/structure/v4/ver4_patricia_trie_node_writer.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_NODE_WRITER_H
 #define LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_NODE_WRITER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/probability_entry.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_writer.h"
+#include "dictionary/structure/backward/v402/content/probability_entry.h"
 #include "utils/int_array_view.h"
 
 namespace latinime {
@@ -94,7 +94,7 @@ class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
             const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos);
 
     virtual bool addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
+            const NgramProperty *const ngramProperty, bool *const outAddedNewEntry);
 
     virtual bool removeNgramEntry(const WordIdArrayView prevWordIds, const int wordId);
 
@@ -111,6 +111,11 @@ class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
 
     bool updatePtNodeHasBigramsAndShortcutTargetsFlags(const PtNodeParams *const ptNodeParams);
 
+    // Suppress unigram not to use the word for generating suggestions. So, this method can be used
+    // only for dictionaries with historical info. Also, suppressed entries are included in unigram
+    // count. They will be removed from the dictionary during GC.
+    bool suppressUnigramEntry(const PtNodeParams *const ptNodeParams);
+
  private:
     DISALLOW_COPY_AND_ASSIGN(Ver4PatriciaTrieNodeWriter);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
index 1296b8acd..6fb9cffb7 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_policy.cpp
@@ -19,24 +19,25 @@
  * Do not edit this file other than updating policy's interface.
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+ *   dictionary/structure/v4/ver4_patricia_trie_policy.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_policy.h"
 
 #include <vector>
 
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_vector.h"
-#include "suggest/core/dictionary/ngram_listener.h"
-#include "suggest/core/dictionary/property/bigram_property.h"
-#include "suggest/core/dictionary/property/unigram_property.h"
-#include "suggest/core/dictionary/property/word_property.h"
-#include "suggest/core/session/prev_words_info.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
-#include "suggest/policyimpl/dictionary/utils/probability_utils.h"
+#include "dictionary/interface/ngram_listener.h"
+#include "dictionary/property/ngram_context.h"
+#include "dictionary/property/ngram_property.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/property/word_property.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/utils/multi_bigram_map.h"
+#include "dictionary/utils/probability_utils.h"
 
 namespace latinime {
 namespace backward {
@@ -51,6 +52,7 @@ const char *const Ver4PatriciaTriePolicy::MAX_BIGRAM_COUNT_QUERY = "MAX_BIGRAM_C
 const int Ver4PatriciaTriePolicy::MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS = 1024;
 const int Ver4PatriciaTriePolicy::MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS =
         Ver4DictConstants::MAX_DICTIONARY_SIZE - MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
+const int Ver4PatriciaTriePolicy::DUMMY_PROBABILITY_FOR_VALID_WORDS = 1;
 
 void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNode,
         DicNodeVector *const childDicNodes) const {
@@ -76,12 +78,9 @@ void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const d
             // Skip PtNodes that represent non-word information.
             continue;
         }
-        childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getHeadPos(),
-                ptNodeParams.getChildrenPos(), ptNodeParams.getProbability(), isTerminal,
-                ptNodeParams.hasChildren(),
-                ptNodeParams.isBlacklisted()
-                        || ptNodeParams.isNotAWord() /* isBlacklistedOrNotAWord */,
-                ptNodeParams.getCodePointCount(), ptNodeParams.getCodePoints());
+        const int wordId = isTerminal ? ptNodeParams.getHeadPos() : NOT_A_WORD_ID;
+        childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getChildrenPos(),
+                wordId, ptNodeParams.getCodePointArrayView());
     }
     if (readingHelper.isError()) {
         mIsCorrupted = true;
@@ -89,13 +88,13 @@ void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const d
     }
 }
 
-int Ver4PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
-        const int ptNodePos, const int maxCodePointCount, int *const outCodePoints,
-        int *const outUnigramProbability) const {
+int Ver4PatriciaTriePolicy::getCodePointsAndReturnCodePointCount(const int wordId,
+        const int maxCodePointCount, int *const outCodePoints) const {
     DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
     readingHelper.initWithPtNodePos(ptNodePos);
-    const int codePointCount =  readingHelper.getCodePointsAndProbabilityAndReturnCodePointCount(
-            maxCodePointCount, outCodePoints, outUnigramProbability);
+    const int codePointCount =  readingHelper.getCodePointsAndReturnCodePointCount(
+            maxCodePointCount, outCodePoints);
     if (readingHelper.isError()) {
         mIsCorrupted = true;
         AKLOGE("Dictionary reading error in getCodePointsAndProbabilityAndReturnCodePointCount().");
@@ -103,72 +102,143 @@ int Ver4PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
     return codePointCount;
 }
 
-int Ver4PatriciaTriePolicy::getTerminalPtNodePositionOfWord(const int *const inWord,
-        const int length, const bool forceLowerCaseSearch) const {
+int Ver4PatriciaTriePolicy::getWordId(const CodePointArrayView wordCodePoints,
+        const bool forceLowerCaseSearch) const {
     DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
     readingHelper.initWithPtNodeArrayPos(getRootPosition());
-    const int ptNodePos =
-            readingHelper.getTerminalPtNodePositionOfWord(inWord, length, forceLowerCaseSearch);
+    const int ptNodePos = readingHelper.getTerminalPtNodePositionOfWord(wordCodePoints.data(),
+            wordCodePoints.size(), forceLowerCaseSearch);
     if (readingHelper.isError()) {
         mIsCorrupted = true;
-        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+        AKLOGE("Dictionary reading error in getWordId().");
+    }
+    return getWordIdFromTerminalPtNodePos(ptNodePos);
+}
+
+const WordAttributes Ver4PatriciaTriePolicy::getWordAttributesInContext(
+        const WordIdArrayView prevWordIds, const int wordId,
+        MultiBigramMap *const multiBigramMap) const {
+    if (wordId == NOT_A_WORD_ID) {
+        return WordAttributes();
     }
-    return ptNodePos;
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
+    const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
+    if (multiBigramMap) {
+        const int probability = multiBigramMap->getBigramProbability(this /* structurePolicy */,
+                prevWordIds, wordId, ptNodeParams.getProbability());
+        return getWordAttributes(probability, ptNodeParams);
+    }
+    if (!prevWordIds.empty()) {
+        const int probability = getProbabilityOfWord(prevWordIds, wordId);
+        if (probability != NOT_A_PROBABILITY) {
+            return getWordAttributes(probability, ptNodeParams);
+        }
+    }
+    return getWordAttributes(getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY),
+            ptNodeParams);
+}
+
+const WordAttributes Ver4PatriciaTriePolicy::getWordAttributes(const int probability,
+        const PtNodeParams &ptNodeParams) const {
+    return WordAttributes(probability, false /* isBlacklisted */, ptNodeParams.isNotAWord(),
+            ptNodeParams.getProbability() == 0);
 }
 
 int Ver4PatriciaTriePolicy::getProbability(const int unigramProbability,
         const int bigramProbability) const {
-    if (mHeaderPolicy->isDecayingDict()) {
-        // Both probabilities are encoded. Decode them and get probability.
-        return ForgettingCurveUtils::getProbability(unigramProbability, bigramProbability);
-    } else {
-        if (unigramProbability == NOT_A_PROBABILITY) {
-            return NOT_A_PROBABILITY;
-        } else if (bigramProbability == NOT_A_PROBABILITY) {
-            return ProbabilityUtils::backoff(unigramProbability);
-        } else {
-            return bigramProbability;
-        }
+    // In the v4 format, bigramProbability is a conditional probability.
+    const int bigramConditionalProbability = bigramProbability;
+    if (unigramProbability == NOT_A_PROBABILITY) {
+        return NOT_A_PROBABILITY;
     }
+    if (bigramConditionalProbability == NOT_A_PROBABILITY) {
+        return ProbabilityUtils::backoff(unigramProbability);
+    }
+    return bigramConditionalProbability;
 }
 
-int Ver4PatriciaTriePolicy::getProbabilityOfPtNode(const int *const prevWordsPtNodePos,
-        const int ptNodePos) const {
-    if (ptNodePos == NOT_A_DICT_POS) {
+int Ver4PatriciaTriePolicy::getProbabilityOfWord(const WordIdArrayView prevWordIds,
+        const int wordId) const {
+    if (wordId == NOT_A_WORD_ID) {
         return NOT_A_PROBABILITY;
     }
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
     const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
-    if (ptNodeParams.isDeleted() || ptNodeParams.isBlacklisted() || ptNodeParams.isNotAWord()) {
+    if (ptNodeParams.isDeleted() || ptNodeParams.isNotAWord()) {
         return NOT_A_PROBABILITY;
     }
-    if (prevWordsPtNodePos) {
-        const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
-        BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
-        while (bigramsIt.hasNext()) {
-            bigramsIt.next();
-            if (bigramsIt.getBigramPos() == ptNodePos
-                    && bigramsIt.getProbability() != NOT_A_PROBABILITY) {
-                return getProbability(ptNodeParams.getProbability(), bigramsIt.getProbability());
-            }
-        }
+    if (prevWordIds.empty()) {
+        return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    }
+    if (prevWordIds[0] == NOT_A_WORD_ID) {
         return NOT_A_PROBABILITY;
     }
-    return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    const PtNodeParams prevWordPtNodeParams =
+            mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(prevWordIds[0]);
+    if (prevWordPtNodeParams.isDeleted()) {
+        return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+    }
+    const int bigramsPosition = mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            prevWordPtNodeParams.getTerminalId());
+    BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
+    while (bigramsIt.hasNext()) {
+        bigramsIt.next();
+        if (bigramsIt.getBigramPos() == ptNodePos
+                && bigramsIt.getProbability() != NOT_A_PROBABILITY) {
+            const int bigramConditionalProbability = getBigramConditionalProbability(
+                    prevWordPtNodeParams.getProbability(),
+                    prevWordPtNodeParams.representsBeginningOfSentence(),
+                    bigramsIt.getProbability());
+            return getProbability(ptNodeParams.getProbability(), bigramConditionalProbability);
+        }
+    }
+    return NOT_A_PROBABILITY;
 }
 
-void Ver4PatriciaTriePolicy::iterateNgramEntries(const int *const prevWordsPtNodePos,
+void Ver4PatriciaTriePolicy::iterateNgramEntries(const WordIdArrayView prevWordIds,
         NgramListener *const listener) const {
-    if (!prevWordsPtNodePos) {
+    if (prevWordIds.firstOrDefault(NOT_A_DICT_POS) == NOT_A_DICT_POS) {
+        return;
+    }
+    const PtNodeParams prevWordPtNodeParams =
+            mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(prevWordIds[0]);
+    if (prevWordPtNodeParams.isDeleted()) {
         return;
     }
-    const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
+    const int bigramsPosition = mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            prevWordPtNodeParams.getTerminalId());
     BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
     while (bigramsIt.hasNext()) {
         bigramsIt.next();
-        listener->onVisitEntry(bigramsIt.getProbability(), bigramsIt.getBigramPos());
+        const int bigramConditionalProbability = getBigramConditionalProbability(
+                prevWordPtNodeParams.getProbability(),
+                prevWordPtNodeParams.representsBeginningOfSentence(), bigramsIt.getProbability());
+        listener->onVisitEntry(bigramConditionalProbability,
+                getWordIdFromTerminalPtNodePos(bigramsIt.getBigramPos()));
     }
 }
 
+int Ver4PatriciaTriePolicy::getBigramConditionalProbability(const int prevWordUnigramProbability,
+        const bool isInBeginningOfSentenceContext, const int bigramProbability) const {
+    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
+        if (isInBeginningOfSentenceContext) {
+            return bigramProbability;
+        }
+        // Calculate conditional probability.
+        return std::min(MAX_PROBABILITY - prevWordUnigramProbability + bigramProbability,
+                MAX_PROBABILITY);
+    } else {
+        // bigramProbability is a conditional probability.
+        return bigramProbability;
+    }
+}
+
+BinaryDictionaryShortcutIterator Ver4PatriciaTriePolicy::getShortcutIterator(
+        const int wordId) const {
+    const int shortcutPos = getShortcutPositionOfPtNode(getTerminalPtNodePosFromWordId(wordId));
+    return BinaryDictionaryShortcutIterator(&mShortcutPolicy, shortcutPos);
+}
+
 int Ver4PatriciaTriePolicy::getShortcutPositionOfPtNode(const int ptNodePos) const {
     if (ptNodePos == NOT_A_DICT_POS) {
         return NOT_A_DICT_POS;
@@ -193,7 +263,7 @@ int Ver4PatriciaTriePolicy::getBigramsPositionOfPtNode(const int ptNodePos) cons
             ptNodeParams.getTerminalId());
 }
 
-bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int length,
+bool Ver4PatriciaTriePolicy::addUnigramEntry(const CodePointArrayView wordCodePoints,
         const UnigramProperty *const unigramProperty) {
     if (!mBuffers->isUpdatable()) {
         AKLOGI("Warning: addUnigramEntry() is called for non-updatable dictionary.");
@@ -204,13 +274,14 @@ bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int le
                 mDictBuffer->getTailPosition());
         return false;
     }
-    if (length > MAX_WORD_LENGTH) {
-        AKLOGE("The word is too long to insert to the dictionary, length: %d", length);
+    if (wordCodePoints.size() > MAX_WORD_LENGTH) {
+        AKLOGE("The word is too long to insert to the dictionary, length: %zd",
+                wordCodePoints.size());
         return false;
     }
     for (const auto &shortcut : unigramProperty->getShortcuts()) {
         if (shortcut.getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
-            AKLOGE("One of shortcut targets is too long to insert to the dictionary, length: %d",
+            AKLOGE("One of shortcut targets is too long to insert to the dictionary, length: %zd",
                     shortcut.getTargetCodePoints()->size());
             return false;
         }
@@ -219,8 +290,8 @@ bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int le
     readingHelper.initWithPtNodeArrayPos(getRootPosition());
     bool addedNewUnigram = false;
     int codePointsToAdd[MAX_WORD_LENGTH];
-    int codePointCountToAdd = length;
-    memmove(codePointsToAdd, word, sizeof(int) * length);
+    int codePointCountToAdd = wordCodePoints.size();
+    memmove(codePointsToAdd, wordCodePoints.data(), sizeof(int) * codePointCountToAdd);
     if (unigramProperty->representsBeginningOfSentence()) {
         codePointCountToAdd = CharUtils::attachBeginningOfSentenceMarker(codePointsToAdd,
                 codePointCountToAdd, MAX_WORD_LENGTH);
@@ -228,24 +299,25 @@ bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int le
     if (codePointCountToAdd <= 0) {
         return false;
     }
-    if (mUpdatingHelper.addUnigramWord(&readingHelper, codePointsToAdd, codePointCountToAdd,
-            unigramProperty, &addedNewUnigram)) {
+    const CodePointArrayView codePointArrayView(codePointsToAdd, codePointCountToAdd);
+    if (mUpdatingHelper.addUnigramWord(&readingHelper, codePointArrayView, unigramProperty,
+            &addedNewUnigram)) {
         if (addedNewUnigram && !unigramProperty->representsBeginningOfSentence()) {
-            mUnigramCount++;
+            mEntryCounters.incrementNgramCount(NgramType::Unigram);
         }
         if (unigramProperty->getShortcuts().size() > 0) {
             // Add shortcut target.
-            const int wordPos = getTerminalPtNodePositionOfWord(word, length,
-                    false /* forceLowerCaseSearch */);
+            const int wordPos = getTerminalPtNodePosFromWordId(
+                    getWordId(codePointArrayView, false /* forceLowerCaseSearch */));
             if (wordPos == NOT_A_DICT_POS) {
                 AKLOGE("Cannot find terminal PtNode position to add shortcut target.");
                 return false;
             }
             for (const auto &shortcut : unigramProperty->getShortcuts()) {
                 if (!mUpdatingHelper.addShortcutTarget(wordPos,
-                        shortcut.getTargetCodePoints()->data(),
-                        shortcut.getTargetCodePoints()->size(), shortcut.getProbability())) {
-                    AKLOGE("Cannot add new shortcut target. PtNodePos: %d, length: %d, "
+                        CodePointArrayView(*shortcut.getTargetCodePoints()),
+                        shortcut.getProbability())) {
+                    AKLOGE("Cannot add new shortcut target. PtNodePos: %d, length: %zd, "
                             "probability: %d", wordPos, shortcut.getTargetCodePoints()->size(),
                             shortcut.getProbability());
                     return false;
@@ -258,8 +330,21 @@ bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int le
     }
 }
 
-bool Ver4PatriciaTriePolicy::addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const BigramProperty *const bigramProperty) {
+bool Ver4PatriciaTriePolicy::removeUnigramEntry(const CodePointArrayView wordCodePoints) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: removeUnigramEntry() is called for non-updatable dictionary.");
+        return false;
+    }
+    const int ptNodePos = getTerminalPtNodePosFromWordId(
+            getWordId(wordCodePoints, false /* forceLowerCaseSearch */));
+    if (ptNodePos == NOT_A_DICT_POS) {
+        return false;
+    }
+    const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
+    return mNodeWriter.suppressUnigramEntry(&ptNodeParams);
+}
+
+bool Ver4PatriciaTriePolicy::addNgramEntry(const NgramProperty *const ngramProperty) {
     if (!mBuffers->isUpdatable()) {
         AKLOGI("Warning: addNgramEntry() is called for non-updatable dictionary.");
         return false;
@@ -269,50 +354,50 @@ bool Ver4PatriciaTriePolicy::addNgramEntry(const PrevWordsInfo *const prevWordsI
                 mDictBuffer->getTailPosition());
         return false;
     }
-    if (!prevWordsInfo->isValid()) {
-        AKLOGE("prev words info is not valid for adding n-gram entry to the dictionary.");
+    const NgramContext *const ngramContext = ngramProperty->getNgramContext();
+    if (!ngramContext->isValid()) {
+        AKLOGE("Ngram context is not valid for adding n-gram entry to the dictionary.");
         return false;
     }
-    if (bigramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
+    if (ngramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
         AKLOGE("The word is too long to insert the ngram to the dictionary. "
-                "length: %d", bigramProperty->getTargetCodePoints()->size());
+                "length: %zd", ngramProperty->getTargetCodePoints()->size());
         return false;
     }
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(this, &prevWordIdArray,
             false /* tryLowerCaseSearch */);
-    // TODO: Support N-gram.
-    if (prevWordsPtNodePos[0] == NOT_A_DICT_POS) {
-        if (prevWordsInfo->isNthPrevWordBeginningOfSentence(1 /* n */)) {
-            const std::vector<UnigramProperty::ShortcutProperty> shortcuts;
+    if (prevWordIds.empty()) {
+        return false;
+    }
+    if (prevWordIds[0] == NOT_A_WORD_ID) {
+        if (ngramContext->isNthPrevWordBeginningOfSentence(1 /* n */)) {
             const UnigramProperty beginningOfSentenceUnigramProperty(
                     true /* representsBeginningOfSentence */, true /* isNotAWord */,
-                    false /* isBlacklisted */, MAX_PROBABILITY /* probability */,
-                    NOT_A_TIMESTAMP /* timestamp */, 0 /* level */, 0 /* count */, &shortcuts);
-            if (!addUnigramEntry(prevWordsInfo->getNthPrevWordCodePoints(1 /* n */),
-                    prevWordsInfo->getNthPrevWordCodePointCount(1 /* n */),
+                    false /* isBlacklisted */, MAX_PROBABILITY /* probability */, HistoricalInfo());
+            if (!addUnigramEntry(ngramContext->getNthPrevWordCodePoints(1 /* n */),
                     &beginningOfSentenceUnigramProperty)) {
                 AKLOGE("Cannot add unigram entry for the beginning-of-sentence.");
                 return false;
             }
-            // Refresh Terminal PtNode positions.
-            prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
-                    false /* tryLowerCaseSearch */);
+            // Refresh word ids.
+            ngramContext->getPrevWordIds(this, &prevWordIdArray, false /* tryLowerCaseSearch */);
         } else {
             return false;
         }
     }
-    const int word1Pos = getTerminalPtNodePositionOfWord(
-            bigramProperty->getTargetCodePoints()->data(),
-            bigramProperty->getTargetCodePoints()->size(), false /* forceLowerCaseSearch */);
-    if (word1Pos == NOT_A_DICT_POS) {
+    const int wordPos = getTerminalPtNodePosFromWordId(getWordId(
+            CodePointArrayView(*ngramProperty->getTargetCodePoints()),
+                    false /* forceLowerCaseSearch */));
+    if (wordPos == NOT_A_DICT_POS) {
         return false;
     }
     bool addedNewBigram = false;
-    if (mUpdatingHelper.addNgramEntry(PtNodePosArrayView::fromObject(prevWordsPtNodePos),
-            word1Pos, bigramProperty, &addedNewBigram)) {
+    const int prevWordPtNodePos = getTerminalPtNodePosFromWordId(prevWordIds[0]);
+    if (mUpdatingHelper.addNgramEntry(PtNodePosArrayView::singleElementView(&prevWordPtNodePos),
+            wordPos, ngramProperty, &addedNewBigram)) {
         if (addedNewBigram) {
-            mBigramCount++;
+            mEntryCounters.incrementNgramCount(NgramType::Bigram);
         }
         return true;
     } else {
@@ -320,8 +405,8 @@ bool Ver4PatriciaTriePolicy::addNgramEntry(const PrevWordsInfo *const prevWordsI
     }
 }
 
-bool Ver4PatriciaTriePolicy::removeNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const int *const word, const int length) {
+bool Ver4PatriciaTriePolicy::removeNgramEntry(const NgramContext *const ngramContext,
+        const CodePointArrayView wordCodePoints) {
     if (!mBuffers->isUpdatable()) {
         AKLOGI("Warning: removeNgramEntry() is called for non-updatable dictionary.");
         return false;
@@ -331,40 +416,68 @@ bool Ver4PatriciaTriePolicy::removeNgramEntry(const PrevWordsInfo *const prevWor
                 mDictBuffer->getTailPosition());
         return false;
     }
-    if (!prevWordsInfo->isValid()) {
-        AKLOGE("prev words info is not valid for removing n-gram entry form the dictionary.");
+    if (!ngramContext->isValid()) {
+        AKLOGE("Ngram context is not valid for removing n-gram entry form the dictionary.");
         return false;
     }
-    if (length > MAX_WORD_LENGTH) {
-        AKLOGE("word is too long to remove n-gram entry form the dictionary. length: %d", length);
+    if (wordCodePoints.size() > MAX_WORD_LENGTH) {
+        AKLOGE("word is too long to remove n-gram entry form the dictionary. length: %zd",
+                wordCodePoints.size());
     }
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(this, &prevWordIdArray,
             false /* tryLowerCaseSerch */);
-    // TODO: Support N-gram.
-    if (prevWordsPtNodePos[0] == NOT_A_DICT_POS) {
+    if (prevWordIds.firstOrDefault(NOT_A_WORD_ID) == NOT_A_WORD_ID) {
         return false;
     }
-    const int wordPos = getTerminalPtNodePositionOfWord(word, length,
-            false /* forceLowerCaseSearch */);
+    const int wordPos = getTerminalPtNodePosFromWordId(getWordId(wordCodePoints,
+            false /* forceLowerCaseSearch */));
     if (wordPos == NOT_A_DICT_POS) {
         return false;
     }
+    const int prevWordPtNodePos = getTerminalPtNodePosFromWordId(prevWordIds[0]);
     if (mUpdatingHelper.removeNgramEntry(
-            PtNodePosArrayView::fromObject(prevWordsPtNodePos), wordPos)) {
-        mBigramCount--;
+            PtNodePosArrayView::singleElementView(&prevWordPtNodePos), wordPos)) {
+        mEntryCounters.decrementNgramCount(NgramType::Bigram);
         return true;
     } else {
         return false;
     }
 }
 
+
+bool Ver4PatriciaTriePolicy::updateEntriesForWordWithNgramContext(
+        const NgramContext *const ngramContext, const CodePointArrayView wordCodePoints,
+        const bool isValidWord, const HistoricalInfo historicalInfo) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: updateEntriesForWordWithNgramContext() is called for non-updatable "
+                "dictionary.");
+        return false;
+    }
+    const int probability = isValidWord ? DUMMY_PROBABILITY_FOR_VALID_WORDS : NOT_A_PROBABILITY;
+    const UnigramProperty unigramProperty(false /* representsBeginningOfSentence */,
+            false /* isNotAWord */, false /*isBlacklisted*/, probability, historicalInfo);
+    if (!addUnigramEntry(wordCodePoints, &unigramProperty)) {
+        AKLOGE("Cannot update unigarm entry in updateEntriesForWordWithNgramContext().");
+        return false;
+    }
+    const int probabilityForNgram = ngramContext->isNthPrevWordBeginningOfSentence(1 /* n */)
+            ? NOT_A_PROBABILITY : probability;
+    const NgramProperty ngramProperty(*ngramContext, wordCodePoints.toVector(), probabilityForNgram,
+            historicalInfo);
+    if (!addNgramEntry(&ngramProperty)) {
+        AKLOGE("Cannot update unigarm entry in updateEntriesForWordWithNgramContext().");
+        return false;
+    }
+    return true;
+}
+
 bool Ver4PatriciaTriePolicy::flush(const char *const filePath) {
     if (!mBuffers->isUpdatable()) {
         AKLOGI("Warning: flush() is called for non-updatable dictionary. filePath: %s", filePath);
         return false;
     }
-    if (!mWritingHelper.writeToDictFile(filePath, mUnigramCount, mBigramCount)) {
+    if (!mWritingHelper.writeToDictFile(filePath, mEntryCounters.getEntryCounts())) {
         AKLOGE("Cannot flush the dictionary to file.");
         mIsCorrupted = true;
         return false;
@@ -402,7 +515,7 @@ bool Ver4PatriciaTriePolicy::needsToRunGC(const bool mindsBlockByGC) const {
         // Needs to reduce dictionary size.
         return true;
     } else if (mHeaderPolicy->isDecayingDict()) {
-        return ForgettingCurveUtils::needsToDecay(mindsBlockByGC, mUnigramCount, mBigramCount,
+        return ForgettingCurveUtils::needsToDecay(mindsBlockByGC, mEntryCounters.getEntryCounts(),
                 mHeaderPolicy);
     }
     return false;
@@ -412,41 +525,42 @@ void Ver4PatriciaTriePolicy::getProperty(const char *const query, const int quer
         char *const outResult, const int maxResultLength) {
     const int compareLength = queryLength + 1 /* terminator */;
     if (strncmp(query, UNIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d", mUnigramCount);
+        snprintf(outResult, maxResultLength, "%d",
+                mEntryCounters.getNgramCount(NgramType::Unigram));
     } else if (strncmp(query, BIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d", mBigramCount);
+        snprintf(outResult, maxResultLength, "%d", mEntryCounters.getNgramCount(NgramType::Bigram));
     } else if (strncmp(query, MAX_UNIGRAM_COUNT_QUERY, compareLength) == 0) {
         snprintf(outResult, maxResultLength, "%d",
                 mHeaderPolicy->isDecayingDict() ?
-                        ForgettingCurveUtils::getUnigramCountHardLimit(
-                                mHeaderPolicy->getMaxUnigramCount()) :
+                        ForgettingCurveUtils::getEntryCountHardLimit(
+                                mHeaderPolicy->getMaxNgramCounts().getNgramCount(
+                                        NgramType::Unigram)) :
                         static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
     } else if (strncmp(query, MAX_BIGRAM_COUNT_QUERY, compareLength) == 0) {
         snprintf(outResult, maxResultLength, "%d",
                 mHeaderPolicy->isDecayingDict() ?
-                        ForgettingCurveUtils::getBigramCountHardLimit(
-                                mHeaderPolicy->getMaxBigramCount()) :
+                        ForgettingCurveUtils::getEntryCountHardLimit(
+                                mHeaderPolicy->getMaxNgramCounts().getNgramCount(
+                                        NgramType::Bigram)) :
                         static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
     }
 }
 
-const WordProperty Ver4PatriciaTriePolicy::getWordProperty(const int *const codePoints,
-        const int codePointCount) const {
-    const int ptNodePos = getTerminalPtNodePositionOfWord(codePoints, codePointCount,
-            false /* forceLowerCaseSearch */);
+const WordProperty Ver4PatriciaTriePolicy::getWordProperty(
+        const CodePointArrayView wordCodePoints) const {
+    const int ptNodePos = getTerminalPtNodePosFromWordId(
+            getWordId(wordCodePoints, false /* forceLowerCaseSearch */));
     if (ptNodePos == NOT_A_DICT_POS) {
         AKLOGE("getWordProperty is called for invalid word.");
         return WordProperty();
     }
     const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-    std::vector<int> codePointVector(ptNodeParams.getCodePoints(),
-            ptNodeParams.getCodePoints() + ptNodeParams.getCodePointCount());
     const ProbabilityEntry probabilityEntry =
             mBuffers->getProbabilityDictContent()->getProbabilityEntry(
                     ptNodeParams.getTerminalId());
     const HistoricalInfo *const historicalInfo = probabilityEntry.getHistoricalInfo();
     // Fetch bigram information.
-    std::vector<BigramProperty> bigrams;
+    std::vector<NgramProperty> ngrams;
     const int bigramListPos = getBigramsPositionOfPtNode(ptNodePos);
     if (bigramListPos != NOT_A_DICT_POS) {
         int bigramWord1CodePoints[MAX_WORD_LENGTH];
@@ -465,21 +579,21 @@ const WordProperty Ver4PatriciaTriePolicy::getWordProperty(const int *const code
             if (word1TerminalPtNodePos == NOT_A_DICT_POS) {
                 continue;
             }
-            // Word (unigram) probability
-            int word1Probability = NOT_A_PROBABILITY;
-            const int codePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
-                    word1TerminalPtNodePos, MAX_WORD_LENGTH, bigramWord1CodePoints,
-                    &word1Probability);
-            const std::vector<int> word1(bigramWord1CodePoints,
-                    bigramWord1CodePoints + codePointCount);
+            const int codePointCount = getCodePointsAndReturnCodePointCount(
+                    getWordIdFromTerminalPtNodePos(word1TerminalPtNodePos), MAX_WORD_LENGTH,
+                    bigramWord1CodePoints);
             const HistoricalInfo *const historicalInfo = bigramEntry.getHistoricalInfo();
-            const int probability = bigramEntry.hasHistoricalInfo() ?
-                    ForgettingCurveUtils::decodeProbability(
-                            bigramEntry.getHistoricalInfo(), mHeaderPolicy) :
-                    bigramEntry.getProbability();
-            bigrams.emplace_back(&word1, probability,
-                    historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
-                    historicalInfo->getCount());
+            const int rawBigramProbability = bigramEntry.hasHistoricalInfo()
+                    ? ForgettingCurveUtils::decodeProbability(
+                            bigramEntry.getHistoricalInfo(), mHeaderPolicy)
+                    : bigramEntry.getProbability();
+            const int probability = getBigramConditionalProbability(ptNodeParams.getProbability(),
+                    ptNodeParams.representsBeginningOfSentence(), rawBigramProbability);
+            ngrams.emplace_back(
+                    NgramContext(wordCodePoints.data(), wordCodePoints.size(),
+                            ptNodeParams.representsBeginningOfSentence()),
+                    CodePointArrayView(bigramWord1CodePoints, codePointCount).toVector(),
+                    probability, *historicalInfo);
         }
     }
     // Fetch shortcut information.
@@ -495,15 +609,15 @@ const WordProperty Ver4PatriciaTriePolicy::getWordProperty(const int *const code
             int shortcutProbability = NOT_A_PROBABILITY;
             shortcutDictContent->getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH, shortcutTarget,
                     &shortcutTargetLength, &shortcutProbability, &hasNext, &shortcutPos);
-            const std::vector<int> target(shortcutTarget, shortcutTarget + shortcutTargetLength);
-            shortcuts.emplace_back(&target, shortcutProbability);
+            shortcuts.emplace_back(
+                    CodePointArrayView(shortcutTarget, shortcutTargetLength).toVector(),
+                    shortcutProbability);
         }
     }
     const UnigramProperty unigramProperty(ptNodeParams.representsBeginningOfSentence(),
-            ptNodeParams.isNotAWord(), ptNodeParams.isBlacklisted(), ptNodeParams.getProbability(),
-            historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
-            historicalInfo->getCount(), &shortcuts);
-    return WordProperty(&codePointVector, &unigramProperty, &bigrams);
+            ptNodeParams.isNotAWord(), ptNodeParams.isPossiblyOffensive(),
+            ptNodeParams.getProbability(), *historicalInfo, std::move(shortcuts));
+    return WordProperty(wordCodePoints.toVector(), unigramProperty, ngrams);
 }
 
 int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outCodePoints,
@@ -524,9 +638,8 @@ int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const
         return 0;
     }
     const int terminalPtNodePos = mTerminalPtNodePositionsForIteratingWords[token];
-    int unigramProbability = NOT_A_PROBABILITY;
-    *outCodePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
-            terminalPtNodePos, MAX_WORD_LENGTH, outCodePoints, &unigramProbability);
+    *outCodePointCount = getCodePointsAndReturnCodePointCount(
+            getWordIdFromTerminalPtNodePos(terminalPtNodePos), MAX_WORD_LENGTH, outCodePoints);
     const int nextToken = token + 1;
     if (nextToken >= terminalPtNodePositionsVectorSize) {
         // All words have been iterated.
@@ -536,6 +649,14 @@ int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const
     return nextToken;
 }
 
+int Ver4PatriciaTriePolicy::getWordIdFromTerminalPtNodePos(const int ptNodePos) const {
+    return ptNodePos == NOT_A_DICT_POS ? NOT_A_WORD_ID : ptNodePos;
+}
+
+int Ver4PatriciaTriePolicy::getTerminalPtNodePosFromWordId(const int wordId) const {
+    return wordId == NOT_A_WORD_ID ? NOT_A_DICT_POS : wordId;
+}
+
 } // namespace v402
 } // namespace backward
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
index 9e989b268..bce5f6bea 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h
@@ -19,7 +19,7 @@
  * Do not edit this file other than updating policy's interface.
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
+ *   dictionary/structure/v4/ver4_patricia_trie_policy.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_POLICY_H
@@ -28,17 +28,21 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
+#include "dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
+#include "dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h"
+#include "dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
+#include "dictionary/utils/binary_dictionary_bigrams_iterator.h"
+#include "dictionary/utils/binary_dictionary_shortcut_iterator.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/entry_counters.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 namespace backward {
@@ -55,6 +59,8 @@ class DicNodeVector;
 namespace backward {
 namespace v402 {
 
+// Word id = Position of a PtNode that represents the word.
+// Max supported n-gram is bigram.
 class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
  public:
     Ver4PatriciaTriePolicy(Ver4DictBuffers::Ver4DictBuffersPtr buffers)
@@ -70,54 +76,50 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
                       &mPtNodeArrayReader, &mBigramPolicy, &mShortcutPolicy),
               mUpdatingHelper(mDictBuffer, &mNodeReader, &mNodeWriter),
               mWritingHelper(mBuffers.get()),
-              mUnigramCount(mHeaderPolicy->getUnigramCount()),
-              mBigramCount(mHeaderPolicy->getBigramCount()),
+              mEntryCounters(mHeaderPolicy->getNgramCounts().getCountArray()),
               mTerminalPtNodePositionsForIteratingWords(), mIsCorrupted(false) {};
 
-    AK_FORCE_INLINE int getRootPosition() const {
+    virtual int getRootPosition() const {
         return 0;
     }
 
     void createAndGetAllChildDicNodes(const DicNode *const dicNode,
             DicNodeVector *const childDicNodes) const;
 
-    int getCodePointsAndProbabilityAndReturnCodePointCount(
-            const int terminalPtNodePos, const int maxCodePointCount, int *const outCodePoints,
-            int *const outUnigramProbability) const;
+    int getCodePointsAndReturnCodePointCount(const int wordId, const int maxCodePointCount,
+            int *const outCodePoints) const;
 
-    int getTerminalPtNodePositionOfWord(const int *const inWord,
-            const int length, const bool forceLowerCaseSearch) const;
+    int getWordId(const CodePointArrayView wordCodePoints, const bool forceLowerCaseSearch) const;
+
+    const WordAttributes getWordAttributesInContext(const WordIdArrayView prevWordIds,
+            const int wordId, MultiBigramMap *const multiBigramMap) const;
 
     int getProbability(const int unigramProbability, const int bigramProbability) const;
 
-    int getProbabilityOfPtNode(const int *const prevWordsPtNodePos, const int ptNodePos) const;
+    int getProbabilityOfWord(const WordIdArrayView prevWordIds, const int wordId) const;
 
-    void iterateNgramEntries(const int *const prevWordsPtNodePos,
+    void iterateNgramEntries(const WordIdArrayView prevWordIds,
             NgramListener *const listener) const;
 
-    int getShortcutPositionOfPtNode(const int ptNodePos) const;
+    BinaryDictionaryShortcutIterator getShortcutIterator(const int wordId) const;
 
     const DictionaryHeaderStructurePolicy *getHeaderStructurePolicy() const {
         return mHeaderPolicy;
     }
 
-    const DictionaryShortcutsStructurePolicy *getShortcutsStructurePolicy() const {
-        return &mShortcutPolicy;
-    }
-
-    bool addUnigramEntry(const int *const word, const int length,
+    bool addUnigramEntry(const CodePointArrayView wordCodePoints,
             const UnigramProperty *const unigramProperty);
 
-    bool removeUnigramEntry(const int *const word, const int length) {
-        // Removing unigram entry is not supported.
-        return false;
-    }
+    bool removeUnigramEntry(const CodePointArrayView wordCodePoints);
+
+    bool addNgramEntry(const NgramProperty *const ngramProperty);
 
-    bool addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const BigramProperty *const bigramProperty);
+    bool removeNgramEntry(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints);
 
-    bool removeNgramEntry(const PrevWordsInfo *const prevWordsInfo, const int *const word1,
-            const int length1);
+    bool updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints, const bool isValidWord,
+            const HistoricalInfo historicalInfo);
 
     bool flush(const char *const filePath);
 
@@ -128,8 +130,7 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     void getProperty(const char *const query, const int queryLength, char *const outResult,
             const int maxResultLength);
 
-    const WordProperty getWordProperty(const int *const codePoints,
-            const int codePointCount) const;
+    const WordProperty getWordProperty(const CodePointArrayView wordCodePoints) const;
 
     int getNextWordAndNextToken(const int token, int *const outCodePoints,
             int *const outCodePointCount);
@@ -149,6 +150,7 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     // prevent the dictionary from overflowing.
     static const int MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
     static const int MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS;
+    static const int DUMMY_PROBABILITY_FOR_VALID_WORDS;
 
     const Ver4DictBuffers::Ver4DictBuffersPtr mBuffers;
     const HeaderPolicy *const mHeaderPolicy;
@@ -160,12 +162,18 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     Ver4PatriciaTrieNodeWriter mNodeWriter;
     DynamicPtUpdatingHelper mUpdatingHelper;
     Ver4PatriciaTrieWritingHelper mWritingHelper;
-    int mUnigramCount;
-    int mBigramCount;
+    MutableEntryCounters mEntryCounters;
     std::vector<int> mTerminalPtNodePositionsForIteratingWords;
     mutable bool mIsCorrupted;
 
     int getBigramsPositionOfPtNode(const int ptNodePos) const;
+    int getShortcutPositionOfPtNode(const int ptNodePos) const;
+    int getWordIdFromTerminalPtNodePos(const int ptNodePos) const;
+    int getTerminalPtNodePosFromWordId(const int wordId) const;
+    const WordAttributes getWordAttributes(const int probability,
+            const PtNodeParams &ptNodeParams) const;
+    int getBigramConditionalProbability(const int prevWordUnigramProbability,
+            const bool isInBeginningOfSentenceContext, const int bigramProbability) const;
 };
 } // namespace v402
 } // namespace backward
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.cpp
index 80d531198..b8a4cf847 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.cpp
@@ -18,12 +18,12 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
+ *   dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h"
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h
index 3579c26d6..c3e736bdc 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_reading_utils.h
@@ -18,7 +18,7 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
+ *   dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_READING_UTILS_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.cpp
index 3fb4caa08..c0af9eae6 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.cpp
@@ -18,43 +18,43 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
+ *   dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h"
 
 #include <cstring>
 #include <queue>
 
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/backward/v402/bigram/ver4_bigram_list_policy.h"
+#include "dictionary/structure/backward/v402/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/file_utils.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 namespace backward {
 namespace v402 {
 
 bool Ver4PatriciaTrieWritingHelper::writeToDictFile(const char *const dictDirPath,
-        const int unigramCount, const int bigramCount) const {
+        const EntryCounts &entryCounts) const {
     const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
     BufferWithExtendableBuffer headerBuffer(
             BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
     const int extendedRegionSize = headerPolicy->getExtendedRegionSize()
             + mBuffers->getTrieBuffer()->getUsedAdditionalBufferSize();
     if (!headerPolicy->fillInAndWriteHeaderToBuffer(false /* updatesLastDecayedTime */,
-            unigramCount, bigramCount, extendedRegionSize, &headerBuffer)) {
+            entryCounts, extendedRegionSize, &headerBuffer)) {
         AKLOGE("Cannot write header structure to buffer. "
                 "updatesLastDecayedTime: %d, unigramCount: %d, bigramCount: %d, "
-                "extendedRegionSize: %d", false, unigramCount, bigramCount,
-                extendedRegionSize);
+                "extendedRegionSize: %d", false, entryCounts.getNgramCount(NgramType::Unigram),
+                entryCounts.getNgramCount(NgramType::Bigram), extendedRegionSize);
         return false;
     }
     return mBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
@@ -73,8 +73,11 @@ bool Ver4PatriciaTrieWritingHelper::writeToDictFileWithGC(const int rootPtNodeAr
     }
     BufferWithExtendableBuffer headerBuffer(
             BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+    MutableEntryCounters entryCounters;
+    entryCounters.setNgramCount(NgramType::Unigram, unigramCount);
+    entryCounters.setNgramCount(NgramType::Bigram, bigramCount);
     if (!headerPolicy->fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
-            unigramCount, bigramCount, 0 /* extendedRegionSize */, &headerBuffer)) {
+            entryCounters.getEntryCounts(), 0 /* extendedRegionSize */, &headerBuffer)) {
         return false;
     }
     return dictBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
@@ -106,7 +109,7 @@ bool Ver4PatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
     }
     const int unigramCount = traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
             .getValidUnigramCount();
-    const int maxUnigramCount = headerPolicy->getMaxUnigramCount();
+    const int maxUnigramCount = headerPolicy->getMaxNgramCounts().getNgramCount(NgramType::Unigram);
     if (headerPolicy->isDecayingDict() && unigramCount > maxUnigramCount) {
         if (!truncateUnigrams(&ptNodeReader, &ptNodeWriter, maxUnigramCount)) {
             AKLOGE("Cannot remove unigrams. current: %d, max: %d", unigramCount,
@@ -123,7 +126,7 @@ bool Ver4PatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
         return false;
     }
     const int bigramCount = traversePolicyToUpdateBigramProbability.getValidBigramEntryCount();
-    const int maxBigramCount = headerPolicy->getMaxBigramCount();
+    const int maxBigramCount = headerPolicy->getMaxNgramCounts().getNgramCount(NgramType::Bigram);
     if (headerPolicy->isDecayingDict() && bigramCount > maxBigramCount) {
         if (!truncateBigrams(maxBigramCount)) {
             AKLOGE("Cannot remove bigrams. current: %d, max: %d", bigramCount, maxBigramCount);
@@ -216,7 +219,7 @@ bool Ver4PatriciaTrieWritingHelper::truncateUnigrams(
                         probabilityEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
                 probabilityEntry.getProbability();
         priorityQueue.push(DictProbability(terminalPos, probability,
-                probabilityEntry.getHistoricalInfo()->getTimeStamp()));
+                probabilityEntry.getHistoricalInfo()->getTimestamp()));
     }
 
     // Delete unigrams.
@@ -263,7 +266,7 @@ bool Ver4PatriciaTrieWritingHelper::truncateBigrams(const int maxBigramCount) {
                             bigramEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
                     bigramEntry.getProbability();
             priorityQueue.push(DictProbability(entryPos, probability,
-                    bigramEntry.getHistoricalInfo()->getTimeStamp()));
+                    bigramEntry.getHistoricalInfo()->getTimestamp()));
         }
     }
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h
index 9034ee656..f2b873826 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_patricia_trie_writing_helper.h
@@ -18,15 +18,16 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
+ *   dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_WRITING_HELPER_H
 #define LATINIME_BACKWARD_V402_VER4_PATRICIA_TRIE_WRITING_HELPER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
+#include "dictionary/structure/backward/v402/content/terminal_position_lookup_table.h"
+#include "dictionary/utils/entry_counters.h"
 
 namespace latinime {
 namespace backward {
@@ -46,8 +47,7 @@ class Ver4PatriciaTrieWritingHelper {
     Ver4PatriciaTrieWritingHelper(Ver4DictBuffers *const buffers)
             : mBuffers(buffers) {}
 
-    bool writeToDictFile(const char *const dictDirPath, const int unigramCount,
-            const int bigramCount) const;
+    bool writeToDictFile(const char *const dictDirPath, const EntryCounts &entryCounts) const;
 
     // This method cannot be const because the original dictionary buffer will be updated to detect
     // useless PtNodes during GC.
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.cpp b/native/jni/src/dictionary/structure/backward/v402/ver4_pt_node_array_reader.cpp
index 537a6d420..d27d70816 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.cpp
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_pt_node_array_reader.cpp
@@ -18,14 +18,14 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.cpp
+ *   dictionary/structure/v4/ver4_pt_node_array_reader.cpp
  */
 
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
+#include "dictionary/structure/backward/v402/ver4_pt_node_array_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h b/native/jni/src/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h
index 4f8056801..0039bf8fc 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h
+++ b/native/jni/src/dictionary/structure/backward/v402/ver4_pt_node_array_reader.h
@@ -18,14 +18,14 @@
  * !!!!! DO NOT EDIT THIS FILE !!!!!
  *
  * This file was generated from
- *   suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h
+ *   dictionary/structure/v4/ver4_pt_node_array_reader.h
  */
 
 #ifndef LATINIME_BACKWARD_V402_VER4_PT_NODE_ARRAY_READER_H
 #define LATINIME_BACKWARD_V402_VER4_PT_NODE_ARRAY_READER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h"
+#include "dictionary/structure/pt_common/pt_node_array_reader.h"
 
 namespace latinime {
 namespace backward {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp b/native/jni/src/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
index e4ea3da16..4470e8568 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
+++ b/native/jni/src/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
@@ -14,23 +14,23 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h"
+#include "dictionary/structure/dictionary_structure_with_buffer_policy_factory.h"
 
 #include <climits>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_patricia_trie_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h"
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/structure/backward/v402/ver4_dict_constants.h"
+#include "dictionary/structure/backward/v402/ver4_patricia_trie_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/v2/patricia_trie_policy.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_policy.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/file_utils.h"
+#include "dictionary/utils/format_utils.h"
+#include "dictionary/utils/mmapped_buffer.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
@@ -58,7 +58,7 @@ namespace latinime {
                 const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap) {
     FormatUtils::FORMAT_VERSION dictFormatVersion = FormatUtils::getFormatVersion(formatVersion);
     switch (dictFormatVersion) {
-        case FormatUtils::VERSION_4: {
+        case FormatUtils::VERSION_402: {
             return newPolicyForOnMemoryV4Dict<backward::v402::Ver4DictConstants,
                     backward::v402::Ver4DictBuffers,
                     backward::v402::Ver4DictBuffers::Ver4DictBuffersPtr,
@@ -66,7 +66,7 @@ namespace latinime {
                             dictFormatVersion, locale, attributeMap);
         }
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
-        case FormatUtils::VERSION_4_DEV: {
+        case FormatUtils::VERSION_403: {
             return newPolicyForOnMemoryV4Dict<Ver4DictConstants, Ver4DictBuffers,
                     Ver4DictBuffers::Ver4DictBuffersPtr, Ver4PatriciaTriePolicy>(
                             dictFormatVersion, locale, attributeMap);
@@ -111,13 +111,14 @@ template<class DictConstants, class DictBuffers, class DictBuffersPtr, class Str
         return nullptr;
     }
     const FormatUtils::FORMAT_VERSION formatVersion = FormatUtils::detectFormatVersion(
-            mmappedBuffer->getReadOnlyByteArrayView().data(),
-            mmappedBuffer->getReadOnlyByteArrayView().size());
+            mmappedBuffer->getReadOnlyByteArrayView());
     switch (formatVersion) {
         case FormatUtils::VERSION_2:
-            AKLOGE("Given path is a directory but the format is version 2. path: %s", path);
+        case FormatUtils::VERSION_201:
+        case FormatUtils::VERSION_202:
+            AKLOGE("Given path is a directory but the format is version 2xx. path: %s", path);
             break;
-        case FormatUtils::VERSION_4: {
+        case FormatUtils::VERSION_402: {
             return newPolicyForV4Dict<backward::v402::Ver4DictConstants,
                     backward::v402::Ver4DictBuffers,
                     backward::v402::Ver4DictBuffers::Ver4DictBuffersPtr,
@@ -125,7 +126,7 @@ template<class DictConstants, class DictBuffers, class DictBuffersPtr, class Str
                             headerFilePath, formatVersion, std::move(mmappedBuffer));
         }
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
-        case FormatUtils::VERSION_4_DEV: {
+        case FormatUtils::VERSION_403: {
             return newPolicyForV4Dict<Ver4DictConstants, Ver4DictBuffers,
                     Ver4DictBuffers::Ver4DictBuffersPtr, Ver4PatriciaTriePolicy>(
                             headerFilePath, formatVersion, std::move(mmappedBuffer));
@@ -174,14 +175,17 @@ template<class DictConstants, class DictBuffers, class DictBuffersPtr, class Str
     if (!mmappedBuffer) {
         return nullptr;
     }
-    switch (FormatUtils::detectFormatVersion(mmappedBuffer->getReadOnlyByteArrayView().data(),
-            mmappedBuffer->getReadOnlyByteArrayView().size())) {
+    switch (FormatUtils::detectFormatVersion(mmappedBuffer->getReadOnlyByteArrayView())) {
         case FormatUtils::VERSION_2:
+        case FormatUtils::VERSION_201:
+            AKLOGE("Dictionary versions 2 and 201 are incompatible with this version");
+            break;
+        case FormatUtils::VERSION_202:
             return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(
                     new PatriciaTriePolicy(std::move(mmappedBuffer)));
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
-        case FormatUtils::VERSION_4:
-        case FormatUtils::VERSION_4_DEV:
+        case FormatUtils::VERSION_402:
+        case FormatUtils::VERSION_403:
             AKLOGE("Given path is a file but the format is version 4. path: %s", path);
             break;
         default:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h b/native/jni/src/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
index 768454d8d..b0c04c0b1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
+++ b/native/jni/src/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
@@ -20,10 +20,10 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/utils/format_utils.h"
+#include "dictionary/utils/mmapped_buffer.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.cpp b/native/jni/src/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.cpp
index f7fd5c071..64f9b6663 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.cpp
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
+#include "dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
@@ -39,32 +39,31 @@ const BigramListReadWriteUtils::BigramFlags
         BigramListReadWriteUtils::MASK_ATTRIBUTE_PROBABILITY = 0x0F;
 
 /* static */ bool BigramListReadWriteUtils::getBigramEntryPropertiesAndAdvancePosition(
-        const uint8_t *const bigramsBuf, const int bufSize, BigramFlags *const outBigramFlags,
+        const ReadOnlyByteArrayView buffer, BigramFlags *const outBigramFlags,
         int *const outTargetPtNodePos, int *const bigramEntryPos) {
-    if (bufSize <= *bigramEntryPos) {
-        AKLOGE("Read invalid pos in getBigramEntryPropertiesAndAdvancePosition(). bufSize: %d, "
-                "bigramEntryPos: %d.", bufSize, *bigramEntryPos);
+    if (static_cast<int>(buffer.size()) <= *bigramEntryPos) {
+        AKLOGE("Read invalid pos in getBigramEntryPropertiesAndAdvancePosition(). bufSize: %zd, "
+                "bigramEntryPos: %d.", buffer.size(), *bigramEntryPos);
         return false;
     }
-    const BigramFlags bigramFlags = ByteArrayUtils::readUint8AndAdvancePosition(bigramsBuf,
+    const BigramFlags bigramFlags = ByteArrayUtils::readUint8AndAdvancePosition(buffer.data(),
             bigramEntryPos);
     if (outBigramFlags) {
         *outBigramFlags = bigramFlags;
     }
-    const int targetPos = getBigramAddressAndAdvancePosition(bigramsBuf, bigramFlags,
-            bigramEntryPos);
+    const int targetPos = getBigramAddressAndAdvancePosition(buffer, bigramFlags, bigramEntryPos);
     if (outTargetPtNodePos) {
         *outTargetPtNodePos = targetPos;
     }
     return true;
 }
 
-/* static */ bool BigramListReadWriteUtils::skipExistingBigrams(const uint8_t *const bigramsBuf,
-        const int bufSize, int *const bigramListPos) {
+/* static */ bool BigramListReadWriteUtils::skipExistingBigrams(const ReadOnlyByteArrayView buffer,
+        int *const bigramListPos) {
     BigramFlags flags;
     do {
-        if (!getBigramEntryPropertiesAndAdvancePosition(bigramsBuf, bufSize, &flags,
-                0 /* outTargetPtNodePos */, bigramListPos)) {
+        if (!getBigramEntryPropertiesAndAdvancePosition(buffer, &flags, 0 /* outTargetPtNodePos */,
+                bigramListPos)) {
             return false;
         }
     } while(hasNext(flags));
@@ -72,18 +71,18 @@ const BigramListReadWriteUtils::BigramFlags
 }
 
 /* static */ int BigramListReadWriteUtils::getBigramAddressAndAdvancePosition(
-        const uint8_t *const bigramsBuf, const BigramFlags flags, int *const pos) {
+        const ReadOnlyByteArrayView buffer, const BigramFlags flags, int *const pos) {
     int offset = 0;
     const int origin = *pos;
     switch (MASK_ATTRIBUTE_ADDRESS_TYPE & flags) {
         case FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE:
-            offset = ByteArrayUtils::readUint8AndAdvancePosition(bigramsBuf, pos);
+            offset = ByteArrayUtils::readUint8AndAdvancePosition(buffer.data(), pos);
             break;
         case FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES:
-            offset = ByteArrayUtils::readUint16AndAdvancePosition(bigramsBuf, pos);
+            offset = ByteArrayUtils::readUint16AndAdvancePosition(buffer.data(), pos);
             break;
         case FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES:
-            offset = ByteArrayUtils::readUint24AndAdvancePosition(bigramsBuf, pos);
+            offset = ByteArrayUtils::readUint24AndAdvancePosition(buffer.data(), pos);
             break;
     }
     if (isOffsetNegative(flags)) {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h b/native/jni/src/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h
index 10f93fb7a..a0f7d5e83 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h
+++ b/native/jni/src/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h
@@ -21,6 +21,7 @@
 #include <cstdlib>
 
 #include "defines.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
@@ -30,8 +31,8 @@ class BigramListReadWriteUtils {
 public:
    typedef uint8_t BigramFlags;
 
-   static bool getBigramEntryPropertiesAndAdvancePosition(const uint8_t *const bigramsBuf,
-           const int bufSize, BigramFlags *const outBigramFlags, int *const outTargetPtNodePos,
+   static bool getBigramEntryPropertiesAndAdvancePosition(const ReadOnlyByteArrayView buffer,
+           BigramFlags *const outBigramFlags, int *const outTargetPtNodePos,
            int *const bigramEntryPos);
 
    static AK_FORCE_INLINE int getProbabilityFromFlags(const BigramFlags flags) {
@@ -43,8 +44,7 @@ public:
    }
 
    // Bigrams reading methods
-   static bool skipExistingBigrams(const uint8_t *const bigramsBuf, const int bufSize,
-           int *const bigramListPos);
+   static bool skipExistingBigrams(const ReadOnlyByteArrayView buffer, int *const bigramListPos);
 
 private:
    DISALLOW_IMPLICIT_CONSTRUCTORS(BigramListReadWriteUtils);
@@ -61,7 +61,7 @@ private:
        return (flags & FLAG_ATTRIBUTE_OFFSET_NEGATIVE) != 0;
    }
 
-   static int getBigramAddressAndAdvancePosition(const uint8_t *const bigramsBuf,
+   static int getBigramAddressAndAdvancePosition(const ReadOnlyByteArrayView buffer,
            const BigramFlags flags, int *const pos);
 };
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
index db1a802d0..b5e2e9dae 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
+#include "dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
 
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_writer.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h
index 2aa402748..8c7ad965b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h
@@ -20,9 +20,9 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/pt_node_writer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
@@ -76,6 +76,7 @@ class DynamicPtGcEventListeners {
         int mValidUnigramCount;
     };
 
+    // TODO: Remove when we stop supporting v402 format.
     // Updates all bigram entries that are held by valid PtNodes. This removes useless bigram
     // entries.
     class TraversePolicyToUpdateBigramProbability
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.cpp b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_helper.cpp
index 086d98b4a..294bc6ea9 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_helper.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h"
+#include "dictionary/structure/pt_common/pt_node_array_reader.h"
 #include "utils/char_utils.h"
 
 namespace latinime {
@@ -175,8 +175,8 @@ bool DynamicPtReadingHelper::traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFi
     return !isError();
 }
 
-int DynamicPtReadingHelper::getCodePointsAndProbabilityAndReturnCodePointCount(
-        const int maxCodePointCount, int *const outCodePoints, int *const outUnigramProbability) {
+int DynamicPtReadingHelper::getCodePointsAndReturnCodePointCount(const int maxCodePointCount,
+        int *const outCodePoints) {
     // This method traverses parent nodes from the terminal by following parent pointers; thus,
     // node code points are stored in the buffer in the reverse order.
     int reverseCodePoints[maxCodePointCount];
@@ -184,11 +184,8 @@ int DynamicPtReadingHelper::getCodePointsAndProbabilityAndReturnCodePointCount(
     // First, read the terminal node and get its probability.
     if (!isValidTerminalNode(terminalPtNodeParams)) {
         // Node at the ptNodePos is not a valid terminal node.
-        *outUnigramProbability = NOT_A_PROBABILITY;
         return 0;
     }
-    // Store terminal node probability.
-    *outUnigramProbability = terminalPtNodeParams.getProbability();
     // Then, following parent node link to the dictionary root and fetch node code points.
     int totalCodePointCount = 0;
     while (!isEnd()) {
@@ -196,7 +193,6 @@ int DynamicPtReadingHelper::getCodePointsAndProbabilityAndReturnCodePointCount(
         totalCodePointCount = getTotalCodePointCount(ptNodeParams);
         if (!ptNodeParams.isValid() || totalCodePointCount > maxCodePointCount) {
             // The ptNodePos is not a valid terminal node position in the dictionary.
-            *outUnigramProbability = NOT_A_PROBABILITY;
             return 0;
         }
         // Store node code points to buffer in the reverse order.
@@ -207,7 +203,6 @@ int DynamicPtReadingHelper::getCodePointsAndProbabilityAndReturnCodePointCount(
     }
     if (isError()) {
         // The node position or the dictionary is invalid.
-        *outUnigramProbability = NOT_A_PROBABILITY;
         return 0;
     }
     // Reverse the stored code points to output them.
@@ -218,9 +213,9 @@ int DynamicPtReadingHelper::getCodePointsAndProbabilityAndReturnCodePointCount(
 }
 
 int DynamicPtReadingHelper::getTerminalPtNodePositionOfWord(const int *const inWord,
-        const int length, const bool forceLowerCaseSearch) {
+        const size_t length, const bool forceLowerCaseSearch) {
     int searchCodePoints[length];
-    for (int i = 0; i < length; ++i) {
+    for (size_t i = 0; i < length; ++i) {
         searchCodePoints[i] = forceLowerCaseSearch ? CharUtils::toLowerCase(inWord[i]) : inWord[i];
     }
     while (!isEnd()) {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_helper.h
index b7262581a..d8ddc7c2b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_helper.h
@@ -21,8 +21,8 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_reader.h"
 
 namespace latinime {
 
@@ -138,12 +138,12 @@ class DynamicPtReadingHelper {
     }
 
     // Return code point count exclude the last read node's code points.
-    AK_FORCE_INLINE int getPrevTotalCodePointCount() const {
+    AK_FORCE_INLINE size_t getPrevTotalCodePointCount() const {
         return mReadingState.mTotalCodePointCountSinceInitialization;
     }
 
     // Return code point count include the last read node's code points.
-    AK_FORCE_INLINE int getTotalCodePointCount(const PtNodeParams &ptNodeParams) const {
+    AK_FORCE_INLINE size_t getTotalCodePointCount(const PtNodeParams &ptNodeParams) const {
         return mReadingState.mTotalCodePointCountSinceInitialization
                 + ptNodeParams.getCodePointCount();
     }
@@ -211,10 +211,9 @@ class DynamicPtReadingHelper {
     bool traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
             TraversingEventListener *const listener);
 
-    int getCodePointsAndProbabilityAndReturnCodePointCount(const int maxCodePointCount,
-            int *const outCodePoints, int *const outUnigramProbability);
+    int getCodePointsAndReturnCodePointCount(const int maxCodePointCount, int *const outCodePoints);
 
-    int getTerminalPtNodePositionOfWord(const int *const inWord, const int length,
+    int getTerminalPtNodePositionOfWord(const int *const inWord, const size_t length,
             const bool forceLowerCaseSearch);
 
  private:
@@ -234,7 +233,7 @@ class DynamicPtReadingHelper {
         int mPos;
         // Remaining node count in the current array.
         int mRemainingPtNodeCountInThisArray;
-        int mTotalCodePointCountSinceInitialization;
+        size_t mTotalCodePointCountSinceInitialization;
         // Counter of PtNodes used to avoid infinite loops caused by broken or malicious links.
         int mTotalPtNodeIndexInThisArrayChain;
         // Counter of PtNode arrays used to avoid infinite loops caused by cyclic links of empty
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.cpp b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_utils.cpp
index 3586b50ab..3eb55ed9b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_utils.cpp
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_utils.h
index b13a075d5..b13a075d5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_utils.h
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
index 3c62e2e56..ccad345c8 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_updating_helper.cpp
@@ -14,31 +14,30 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
+#include "dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
 
-#include "suggest/core/dictionary/property/unigram_property.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/pt_common/pt_node_reader.h"
+#include "dictionary/structure/pt_common/pt_node_writer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
 const int DynamicPtUpdatingHelper::CHILDREN_POSITION_FIELD_SIZE = 3;
 
-bool DynamicPtUpdatingHelper::addUnigramWord(
-        DynamicPtReadingHelper *const readingHelper,
-        const int *const wordCodePoints, const int codePointCount,
-        const UnigramProperty *const unigramProperty, bool *const outAddedNewUnigram) {
+bool DynamicPtUpdatingHelper::addUnigramWord(DynamicPtReadingHelper *const readingHelper,
+        const CodePointArrayView wordCodePoints, const UnigramProperty *const unigramProperty,
+        bool *const outAddedNewUnigram) {
     int parentPos = NOT_A_DICT_POS;
     while (!readingHelper->isEnd()) {
         const PtNodeParams ptNodeParams(readingHelper->getPtNodeParams());
         if (!ptNodeParams.isValid()) {
             break;
         }
-        const int matchedCodePointCount = readingHelper->getPrevTotalCodePointCount();
+        const size_t matchedCodePointCount = readingHelper->getPrevTotalCodePointCount();
         if (!readingHelper->isMatchedCodePoint(ptNodeParams, 0 /* index */,
                 wordCodePoints[matchedCodePointCount])) {
             // The first code point is different from target code point. Skip this node and read
@@ -47,26 +46,25 @@ bool DynamicPtUpdatingHelper::addUnigramWord(
             continue;
         }
         // Check following merged node code points.
-        const int nodeCodePointCount = ptNodeParams.getCodePointCount();
-        for (int j = 1; j < nodeCodePointCount; ++j) {
-            const int nextIndex = matchedCodePointCount + j;
-            if (nextIndex >= codePointCount || !readingHelper->isMatchedCodePoint(ptNodeParams, j,
-                    wordCodePoints[matchedCodePointCount + j])) {
+        const size_t nodeCodePointCount = ptNodeParams.getCodePointArrayView().size();
+        for (size_t j = 1; j < nodeCodePointCount; ++j) {
+            const size_t nextIndex = matchedCodePointCount + j;
+            if (nextIndex >= wordCodePoints.size()
+                    || !readingHelper->isMatchedCodePoint(ptNodeParams, j,
+                            wordCodePoints[matchedCodePointCount + j])) {
                 *outAddedNewUnigram = true;
                 return reallocatePtNodeAndAddNewPtNodes(&ptNodeParams, j, unigramProperty,
-                        wordCodePoints + matchedCodePointCount,
-                        codePointCount - matchedCodePointCount);
+                        wordCodePoints.skip(matchedCodePointCount));
             }
         }
         // All characters are matched.
-        if (codePointCount == readingHelper->getTotalCodePointCount(ptNodeParams)) {
+        if (wordCodePoints.size() == readingHelper->getTotalCodePointCount(ptNodeParams)) {
             return setPtNodeProbability(&ptNodeParams, unigramProperty, outAddedNewUnigram);
         }
         if (!ptNodeParams.hasChildren()) {
             *outAddedNewUnigram = true;
             return createChildrenPtNodeArrayAndAChildPtNode(&ptNodeParams, unigramProperty,
-                    wordCodePoints + readingHelper->getTotalCodePointCount(ptNodeParams),
-                    codePointCount - readingHelper->getTotalCodePointCount(ptNodeParams));
+                    wordCodePoints.skip(readingHelper->getTotalCodePointCount(ptNodeParams)));
         }
         // Advance to the children nodes.
         parentPos = ptNodeParams.getHeadPos();
@@ -79,13 +77,12 @@ bool DynamicPtUpdatingHelper::addUnigramWord(
     int pos = readingHelper->getPosOfLastForwardLinkField();
     *outAddedNewUnigram = true;
     return createAndInsertNodeIntoPtNodeArray(parentPos,
-            wordCodePoints + readingHelper->getPrevTotalCodePointCount(),
-            codePointCount - readingHelper->getPrevTotalCodePointCount(),
-            unigramProperty, &pos);
+            wordCodePoints.skip(readingHelper->getPrevTotalCodePointCount()), unigramProperty,
+            &pos);
 }
 
 bool DynamicPtUpdatingHelper::addNgramEntry(const PtNodePosArrayView prevWordsPtNodePos,
-        const int wordPos, const BigramProperty *const bigramProperty,
+        const int wordPos, const NgramProperty *const ngramProperty,
         bool *const outAddedNewEntry) {
     if (prevWordsPtNodePos.empty()) {
         return false;
@@ -99,7 +96,7 @@ bool DynamicPtUpdatingHelper::addNgramEntry(const PtNodePosArrayView prevWordsPt
     const WordIdArrayView prevWordIds(prevWordTerminalIds, prevWordsPtNodePos.size());
     const int wordId =
             mPtNodeReader->fetchPtNodeParamsInBufferFromPtNodePos(wordPos).getTerminalId();
-    return mPtNodeWriter->addNgramEntry(prevWordIds, wordId, bigramProperty, outAddedNewEntry);
+    return mPtNodeWriter->addNgramEntry(prevWordIds, wordId, ngramProperty, outAddedNewEntry);
 }
 
 bool DynamicPtUpdatingHelper::removeNgramEntry(const PtNodePosArrayView prevWordsPtNodePos,
@@ -120,23 +117,21 @@ bool DynamicPtUpdatingHelper::removeNgramEntry(const PtNodePosArrayView prevWord
 }
 
 bool DynamicPtUpdatingHelper::addShortcutTarget(const int wordPos,
-        const int *const targetCodePoints, const int targetCodePointCount,
-        const int shortcutProbability) {
+        const CodePointArrayView targetCodePoints, const int shortcutProbability) {
     const PtNodeParams ptNodeParams(mPtNodeReader->fetchPtNodeParamsInBufferFromPtNodePos(wordPos));
-    return mPtNodeWriter->addShortcutTarget(&ptNodeParams, targetCodePoints, targetCodePointCount,
-            shortcutProbability);
+    return mPtNodeWriter->addShortcutTarget(&ptNodeParams, targetCodePoints.data(),
+            targetCodePoints.size(), shortcutProbability);
 }
 
 bool DynamicPtUpdatingHelper::createAndInsertNodeIntoPtNodeArray(const int parentPos,
-        const int *const nodeCodePoints, const int nodeCodePointCount,
-        const UnigramProperty *const unigramProperty, int *const forwardLinkFieldPos) {
+        const CodePointArrayView ptNodeCodePoints, const UnigramProperty *const unigramProperty,
+        int *const forwardLinkFieldPos) {
     const int newPtNodeArrayPos = mBuffer->getTailPosition();
     if (!DynamicPtWritingUtils::writeForwardLinkPositionAndAdvancePosition(mBuffer,
             newPtNodeArrayPos, forwardLinkFieldPos)) {
         return false;
     }
-    return createNewPtNodeArrayWithAChildPtNode(parentPos, nodeCodePoints, nodeCodePointCount,
-            unigramProperty);
+    return createNewPtNodeArrayWithAChildPtNode(parentPos, ptNodeCodePoints, unigramProperty);
 }
 
 bool DynamicPtUpdatingHelper::setPtNodeProbability(const PtNodeParams *const originalPtNodeParams,
@@ -151,10 +146,9 @@ bool DynamicPtUpdatingHelper::setPtNodeProbability(const PtNodeParams *const ori
         const int movedPos = mBuffer->getTailPosition();
         int writingPos = movedPos;
         const PtNodeParams ptNodeParamsToWrite(getUpdatedPtNodeParams(originalPtNodeParams,
-                unigramProperty->isNotAWord(), unigramProperty->isBlacklisted(),
+                unigramProperty->isNotAWord(), unigramProperty->isPossiblyOffensive(),
                 true /* isTerminal */, originalPtNodeParams->getParentPos(),
-                originalPtNodeParams->getCodePointCount(), originalPtNodeParams->getCodePoints(),
-                unigramProperty->getProbability()));
+                originalPtNodeParams->getCodePointArrayView(), unigramProperty->getProbability()));
         if (!mPtNodeWriter->writeNewTerminalPtNodeAndAdvancePosition(&ptNodeParamsToWrite,
                 unigramProperty, &writingPos)) {
             return false;
@@ -168,17 +162,17 @@ bool DynamicPtUpdatingHelper::setPtNodeProbability(const PtNodeParams *const ori
 
 bool DynamicPtUpdatingHelper::createChildrenPtNodeArrayAndAChildPtNode(
         const PtNodeParams *const parentPtNodeParams, const UnigramProperty *const unigramProperty,
-        const int *const codePoints, const int codePointCount) {
+        const CodePointArrayView codePoints) {
     const int newPtNodeArrayPos = mBuffer->getTailPosition();
     if (!mPtNodeWriter->updateChildrenPosition(parentPtNodeParams, newPtNodeArrayPos)) {
         return false;
     }
     return createNewPtNodeArrayWithAChildPtNode(parentPtNodeParams->getHeadPos(), codePoints,
-            codePointCount, unigramProperty);
+            unigramProperty);
 }
 
 bool DynamicPtUpdatingHelper::createNewPtNodeArrayWithAChildPtNode(
-        const int parentPtNodePos, const int *const nodeCodePoints, const int nodeCodePointCount,
+        const int parentPtNodePos, const CodePointArrayView ptNodeCodePoints,
         const UnigramProperty *const unigramProperty) {
     int writingPos = mBuffer->getTailPosition();
     if (!DynamicPtWritingUtils::writePtNodeArraySizeAndAdvancePosition(mBuffer,
@@ -186,8 +180,8 @@ bool DynamicPtUpdatingHelper::createNewPtNodeArrayWithAChildPtNode(
         return false;
     }
     const PtNodeParams ptNodeParamsToWrite(getPtNodeParamsForNewPtNode(
-            unigramProperty->isNotAWord(), unigramProperty->isBlacklisted(), true /* isTerminal */,
-            parentPtNodePos, nodeCodePointCount, nodeCodePoints,
+            unigramProperty->isNotAWord(), unigramProperty->isPossiblyOffensive(),
+            true /* isTerminal */, parentPtNodePos, ptNodeCodePoints,
             unigramProperty->getProbability()));
     if (!mPtNodeWriter->writeNewTerminalPtNodeAndAdvancePosition(&ptNodeParamsToWrite,
             unigramProperty, &writingPos)) {
@@ -202,9 +196,9 @@ bool DynamicPtUpdatingHelper::createNewPtNodeArrayWithAChildPtNode(
 
 // Returns whether the dictionary updating was succeeded or not.
 bool DynamicPtUpdatingHelper::reallocatePtNodeAndAddNewPtNodes(
-        const PtNodeParams *const reallocatingPtNodeParams, const int overlappingCodePointCount,
-        const UnigramProperty *const unigramProperty, const int *const newNodeCodePoints,
-        const int newNodeCodePointCount) {
+        const PtNodeParams *const reallocatingPtNodeParams, const size_t overlappingCodePointCount,
+        const UnigramProperty *const unigramProperty,
+        const CodePointArrayView newPtNodeCodePoints) {
     // When addsExtraChild is true, split the reallocating PtNode and add new child.
     // Reallocating PtNode: abcde, newNode: abcxy.
     // abc (1st, not terminal) __ de (2nd)
@@ -212,25 +206,26 @@ bool DynamicPtUpdatingHelper::reallocatePtNodeAndAddNewPtNodes(
     // Otherwise, this method makes 1st part terminal and write information in unigramProperty.
     // Reallocating PtNode: abcde, newNode: abc.
     // abc (1st, terminal) __ de (2nd)
-    const bool addsExtraChild = newNodeCodePointCount > overlappingCodePointCount;
+    const bool addsExtraChild = newPtNodeCodePoints.size() > overlappingCodePointCount;
     const int firstPartOfReallocatedPtNodePos = mBuffer->getTailPosition();
     int writingPos = firstPartOfReallocatedPtNodePos;
     // Write the 1st part of the reallocating node. The children position will be updated later
     // with actual children position.
+    const CodePointArrayView firstPtNodeCodePoints =
+            reallocatingPtNodeParams->getCodePointArrayView().limit(overlappingCodePointCount);
     if (addsExtraChild) {
         const PtNodeParams ptNodeParamsToWrite(getPtNodeParamsForNewPtNode(
-                false /* isNotAWord */, false /* isBlacklisted */, false /* isTerminal */,
-                reallocatingPtNodeParams->getParentPos(), overlappingCodePointCount,
-                reallocatingPtNodeParams->getCodePoints(), NOT_A_PROBABILITY));
+                false /* isNotAWord */, false /* isPossiblyOffensive */, false /* isTerminal */,
+                reallocatingPtNodeParams->getParentPos(), firstPtNodeCodePoints,
+                NOT_A_PROBABILITY));
         if (!mPtNodeWriter->writePtNodeAndAdvancePosition(&ptNodeParamsToWrite, &writingPos)) {
             return false;
         }
     } else {
         const PtNodeParams ptNodeParamsToWrite(getPtNodeParamsForNewPtNode(
-                unigramProperty->isNotAWord(), unigramProperty->isBlacklisted(),
+                unigramProperty->isNotAWord(), unigramProperty->isPossiblyOffensive(),
                 true /* isTerminal */, reallocatingPtNodeParams->getParentPos(),
-                overlappingCodePointCount, reallocatingPtNodeParams->getCodePoints(),
-                unigramProperty->getProbability()));
+                firstPtNodeCodePoints, unigramProperty->getProbability()));
         if (!mPtNodeWriter->writeNewTerminalPtNodeAndAdvancePosition(&ptNodeParamsToWrite,
                 unigramProperty, &writingPos)) {
             return false;
@@ -246,20 +241,19 @@ bool DynamicPtUpdatingHelper::reallocatePtNodeAndAddNewPtNodes(
     // Write the 2nd part of the reallocating node.
     const int secondPartOfReallocatedPtNodePos = writingPos;
     const PtNodeParams childPartPtNodeParams(getUpdatedPtNodeParams(reallocatingPtNodeParams,
-            reallocatingPtNodeParams->isNotAWord(), reallocatingPtNodeParams->isBlacklisted(),
+            reallocatingPtNodeParams->isNotAWord(), reallocatingPtNodeParams->isPossiblyOffensive(),
             reallocatingPtNodeParams->isTerminal(), firstPartOfReallocatedPtNodePos,
-            reallocatingPtNodeParams->getCodePointCount() - overlappingCodePointCount,
-            reallocatingPtNodeParams->getCodePoints() + overlappingCodePointCount,
+            reallocatingPtNodeParams->getCodePointArrayView().skip(overlappingCodePointCount),
             reallocatingPtNodeParams->getProbability()));
     if (!mPtNodeWriter->writePtNodeAndAdvancePosition(&childPartPtNodeParams, &writingPos)) {
         return false;
     }
     if (addsExtraChild) {
         const PtNodeParams extraChildPtNodeParams(getPtNodeParamsForNewPtNode(
-                unigramProperty->isNotAWord(), unigramProperty->isBlacklisted(),
+                unigramProperty->isNotAWord(), unigramProperty->isPossiblyOffensive(),
                 true /* isTerminal */, firstPartOfReallocatedPtNodePos,
-                newNodeCodePointCount - overlappingCodePointCount,
-                newNodeCodePoints + overlappingCodePointCount, unigramProperty->getProbability()));
+                newPtNodeCodePoints.skip(overlappingCodePointCount),
+                unigramProperty->getProbability()));
         if (!mPtNodeWriter->writeNewTerminalPtNodeAndAdvancePosition(&extraChildPtNodeParams,
                 unigramProperty, &writingPos)) {
             return false;
@@ -282,26 +276,24 @@ bool DynamicPtUpdatingHelper::reallocatePtNodeAndAddNewPtNodes(
 }
 
 const PtNodeParams DynamicPtUpdatingHelper::getUpdatedPtNodeParams(
-        const PtNodeParams *const originalPtNodeParams,
-        const bool isNotAWord, const bool isBlacklisted, const bool isTerminal, const int parentPos,
-        const int codePointCount, const int *const codePoints, const int probability) const {
+        const PtNodeParams *const originalPtNodeParams, const bool isNotAWord,
+        const bool isPossiblyOffensive, const bool isTerminal, const int parentPos,
+        const CodePointArrayView codePoints, const int probability) const {
     const PatriciaTrieReadingUtils::NodeFlags flags = PatriciaTrieReadingUtils::createAndGetFlags(
-            isBlacklisted, isNotAWord, isTerminal, false /* hasShortcutTargets */,
-            false /* hasBigrams */, codePointCount > 1 /* hasMultipleChars */,
+            isPossiblyOffensive, isNotAWord, isTerminal, false /* hasShortcutTargets */,
+            false /* hasBigrams */, codePoints.size() > 1u /* hasMultipleChars */,
             CHILDREN_POSITION_FIELD_SIZE);
-    return PtNodeParams(originalPtNodeParams, flags, parentPos, codePointCount, codePoints,
-            probability);
+    return PtNodeParams(originalPtNodeParams, flags, parentPos, codePoints, probability);
 }
 
-const PtNodeParams DynamicPtUpdatingHelper::getPtNodeParamsForNewPtNode(
-        const bool isNotAWord, const bool isBlacklisted, const bool isTerminal,
-        const int parentPos, const int codePointCount, const int *const codePoints,
-        const int probability) const {
+const PtNodeParams DynamicPtUpdatingHelper::getPtNodeParamsForNewPtNode(const bool isNotAWord,
+        const bool isPossiblyOffensive, const bool isTerminal, const int parentPos,
+        const CodePointArrayView codePoints, const int probability) const {
     const PatriciaTrieReadingUtils::NodeFlags flags = PatriciaTrieReadingUtils::createAndGetFlags(
-            isBlacklisted, isNotAWord, isTerminal, false /* hasShortcutTargets */,
-            false /* hasBigrams */, codePointCount > 1 /* hasMultipleChars */,
+            isPossiblyOffensive, isNotAWord, isTerminal, false /* hasShortcutTargets */,
+            false /* hasBigrams */, codePoints.size() > 1u /* hasMultipleChars */,
             CHILDREN_POSITION_FIELD_SIZE);
-    return PtNodeParams(flags, parentPos, codePointCount, codePoints, probability);
+    return PtNodeParams(flags, parentPos, codePoints, probability);
 }
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
index 97c05c1ea..e8cf98c39 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_updating_helper.h
@@ -18,12 +18,12 @@
 #define LATINIME_DYNAMIC_PT_UPDATING_HELPER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
 #include "utils/int_array_view.h"
 
 namespace latinime {
 
-class BigramProperty;
+class NgramProperty;
 class BufferWithExtendableBuffer;
 class DynamicPtReadingHelper;
 class PtNodeReader;
@@ -40,19 +40,21 @@ class DynamicPtUpdatingHelper {
 
     // Add a word to the dictionary. If the word already exists, update the probability.
     bool addUnigramWord(DynamicPtReadingHelper *const readingHelper,
-            const int *const wordCodePoints, const int codePointCount,
-            const UnigramProperty *const unigramProperty, bool *const outAddedNewUnigram);
+            const CodePointArrayView wordCodePoints, const UnigramProperty *const unigramProperty,
+            bool *const outAddedNewUnigram);
 
+    // TODO: Remove after stopping supporting v402.
     // Add an n-gram entry.
     bool addNgramEntry(const PtNodePosArrayView prevWordsPtNodePos, const int wordPos,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
+            const NgramProperty *const ngramProperty, bool *const outAddedNewEntry);
 
+    // TODO: Remove after stopping supporting v402.
     // Remove an n-gram entry.
     bool removeNgramEntry(const PtNodePosArrayView prevWordsPtNodePos, const int wordPos);
 
     // Add a shortcut target.
-    bool addShortcutTarget(const int wordPos, const int *const targetCodePoints,
-            const int targetCodePointCount, const int shortcutProbability);
+    bool addShortcutTarget(const int wordPos, const CodePointArrayView targetCodePoints,
+            const int shortcutProbability);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicPtUpdatingHelper);
@@ -63,33 +65,32 @@ class DynamicPtUpdatingHelper {
     const PtNodeReader *const mPtNodeReader;
     PtNodeWriter *const mPtNodeWriter;
 
-    bool createAndInsertNodeIntoPtNodeArray(const int parentPos, const int *const nodeCodePoints,
-            const int nodeCodePointCount, const UnigramProperty *const unigramProperty,
+    bool createAndInsertNodeIntoPtNodeArray(const int parentPos,
+            const CodePointArrayView ptNodeCodePoints, const UnigramProperty *const unigramProperty,
             int *const forwardLinkFieldPos);
 
     bool setPtNodeProbability(const PtNodeParams *const originalPtNodeParams,
             const UnigramProperty *const unigramProperty, bool *const outAddedNewUnigram);
 
     bool createChildrenPtNodeArrayAndAChildPtNode(const PtNodeParams *const parentPtNodeParams,
-            const UnigramProperty *const unigramProperty, const int *const codePoints,
-            const int codePointCount);
+            const UnigramProperty *const unigramProperty,
+            const CodePointArrayView remainingCodePoints);
 
-    bool createNewPtNodeArrayWithAChildPtNode(const int parentPos, const int *const nodeCodePoints,
-            const int nodeCodePointCount, const UnigramProperty *const unigramProperty);
+    bool createNewPtNodeArrayWithAChildPtNode(const int parentPos,
+            const CodePointArrayView ptNodeCodePoints,
+            const UnigramProperty *const unigramProperty);
 
-    bool reallocatePtNodeAndAddNewPtNodes(
-            const PtNodeParams *const reallocatingPtNodeParams, const int overlappingCodePointCount,
-            const UnigramProperty *const unigramProperty, const int *const newNodeCodePoints,
-            const int newNodeCodePointCount);
+    bool reallocatePtNodeAndAddNewPtNodes(const PtNodeParams *const reallocatingPtNodeParams,
+            const size_t overlappingCodePointCount, const UnigramProperty *const unigramProperty,
+            const CodePointArrayView newPtNodeCodePoints);
 
     const PtNodeParams getUpdatedPtNodeParams(const PtNodeParams *const originalPtNodeParams,
-            const bool isNotAWord, const bool isBlacklisted, const bool isTerminal,
-            const int parentPos, const int codePointCount,
-            const int *const codePoints, const int probability) const;
+            const bool isNotAWord, const bool isPossiblyOffensive, const bool isTerminal,
+            const int parentPos, const CodePointArrayView codePoints, const int probability) const;
 
-    const PtNodeParams getPtNodeParamsForNewPtNode(const bool isNotAWord, const bool isBlacklisted,
-            const bool isTerminal, const int parentPos,
-            const int codePointCount, const int *const codePoints, const int probability) const;
+    const PtNodeParams getPtNodeParamsForNewPtNode(const bool isNotAWord,
+            const bool isPossiblyOffensive, const bool isTerminal, const int parentPos,
+            const CodePointArrayView codePoints, const int probability) const;
 };
 } // namespace latinime
 #endif /* LATINIME_DYNAMIC_PATRICIA_TRIE_UPDATING_HELPER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.cpp b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_writing_utils.cpp
index 664aeebbb..ea760a538 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_writing_utils.cpp
@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
 
 #include <cstddef>
 #include <cstdint>
 #include <cstdlib>
 
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_writing_utils.h
index 362fbd1cc..b4817af41 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h
+++ b/native/jni/src/dictionary/structure/pt_common/dynamic_pt_writing_utils.h
@@ -20,7 +20,7 @@
 #include <cstddef>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.cpp b/native/jni/src/dictionary/structure/pt_common/patricia_trie_reading_utils.cpp
index e64a13cc4..e2807c492 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/patricia_trie_reading_utils.cpp
@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
-#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/interface/dictionary_bigrams_structure_policy.h"
+#include "dictionary/interface/dictionary_shortcuts_structure_policy.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
@@ -41,8 +41,8 @@ const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_HAS_SHORTCUT_TARGETS = 0x08
 const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_HAS_BIGRAMS = 0x04;
 // Flag for non-words (typically, shortcut only entries)
 const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_NOT_A_WORD = 0x02;
-// Flag for blacklist
-const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_BLACKLISTED = 0x01;
+// Flag for possibly offensive words
+const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_POSSIBLY_OFFENSIVE = 0x01;
 
 /* static */ int PtReadingUtils::getPtNodeArraySizeAndAdvancePosition(
         const uint8_t *const buffer, int *const pos) {
@@ -61,19 +61,20 @@ const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_BLACKLISTED = 0x01;
 }
 
 /* static */ int PtReadingUtils::getCodePointAndAdvancePosition(const uint8_t *const buffer,
-        int *const pos) {
-    return ByteArrayUtils::readCodePointAndAdvancePosition(buffer, pos);
+        const int *const codePointTable, int *const pos) {
+    return ByteArrayUtils::readCodePointAndAdvancePosition(buffer, codePointTable, pos);
 }
 
 // Returns the number of read characters.
 /* static */ int PtReadingUtils::getCharsAndAdvancePosition(const uint8_t *const buffer,
-        const NodeFlags flags, const int maxLength, int *const outBuffer, int *const pos) {
+        const NodeFlags flags, const int maxLength, const int *const codePointTable,
+        int *const outBuffer, int *const pos) {
     int length = 0;
     if (hasMultipleChars(flags)) {
-        length = ByteArrayUtils::readStringAndAdvancePosition(buffer, maxLength, outBuffer,
-                pos);
+        length = ByteArrayUtils::readStringAndAdvancePosition(buffer, maxLength, codePointTable,
+                outBuffer, pos);
     } else {
-        const int codePoint = getCodePointAndAdvancePosition(buffer, pos);
+        const int codePoint = getCodePointAndAdvancePosition(buffer, codePointTable, pos);
         if (codePoint == NOT_A_CODE_POINT) {
             // CAVEAT: codePoint == NOT_A_CODE_POINT means the code point is
             // CHARACTER_ARRAY_TERMINATOR. The code point must not be CHARACTER_ARRAY_TERMINATOR
@@ -92,12 +93,12 @@ const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_BLACKLISTED = 0x01;
 
 // Returns the number of skipped characters.
 /* static */ int PtReadingUtils::skipCharacters(const uint8_t *const buffer, const NodeFlags flags,
-        const int maxLength, int *const pos) {
+        const int maxLength, const int *const codePointTable, int *const pos) {
     if (hasMultipleChars(flags)) {
         return ByteArrayUtils::advancePositionToBehindString(buffer, maxLength, pos);
     } else {
         if (maxLength > 0) {
-            getCodePointAndAdvancePosition(buffer, pos);
+            getCodePointAndAdvancePosition(buffer, codePointTable, pos);
             return 1;
         } else {
             return 0;
@@ -134,7 +135,7 @@ const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_BLACKLISTED = 0x01;
 
 /* static */ void PtReadingUtils::readPtNodeInfo(const uint8_t *const dictBuf, const int ptNodePos,
         const DictionaryShortcutsStructurePolicy *const shortcutPolicy,
-        const DictionaryBigramsStructurePolicy *const bigramPolicy,
+        const DictionaryBigramsStructurePolicy *const bigramPolicy, const int *const codePointTable,
         NodeFlags *const outFlags, int *const outCodePointCount, int *const outCodePoint,
         int *const outProbability, int *const outChildrenPos, int *const outShortcutPos,
         int *const outBigramPos, int *const outSiblingPos) {
@@ -142,7 +143,7 @@ const PtReadingUtils::NodeFlags PtReadingUtils::FLAG_IS_BLACKLISTED = 0x01;
     const NodeFlags flags = getFlagsAndAdvancePosition(dictBuf, &readingPos);
     *outFlags = flags;
     *outCodePointCount = getCharsAndAdvancePosition(
-            dictBuf, flags, MAX_WORD_LENGTH, outCodePoint, &readingPos);
+            dictBuf, flags, MAX_WORD_LENGTH, codePointTable, outCodePoint, &readingPos);
     *outProbability = isTerminal(flags) ?
             readProbabilityAndAdvancePosition(dictBuf, &readingPos) : NOT_A_PROBABILITY;
     *outChildrenPos = hasChildrenInFlags(flags) ?
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h b/native/jni/src/dictionary/structure/pt_common/patricia_trie_reading_utils.h
index c3f09c3b1..6a2bf5d3c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h
+++ b/native/jni/src/dictionary/structure/pt_common/patricia_trie_reading_utils.h
@@ -34,15 +34,17 @@ class PatriciaTrieReadingUtils {
 
     static NodeFlags getFlagsAndAdvancePosition(const uint8_t *const buffer, int *const pos);
 
-    static int getCodePointAndAdvancePosition(const uint8_t *const buffer, int *const pos);
+    static int getCodePointAndAdvancePosition(const uint8_t *const buffer,
+            const int *const codePointTable, int *const pos);
 
     // Returns the number of read characters.
     static int getCharsAndAdvancePosition(const uint8_t *const buffer, const NodeFlags flags,
-            const int maxLength, int *const outBuffer, int *const pos);
+            const int maxLength, const int *const codePointTable, int *const outBuffer,
+            int *const pos);
 
     // Returns the number of skipped characters.
     static int skipCharacters(const uint8_t *const buffer, const NodeFlags flags,
-            const int maxLength, int *const pos);
+            const int maxLength, const int *const codePointTable, int *const pos);
 
     static int readProbabilityAndAdvancePosition(const uint8_t *const buffer, int *const pos);
 
@@ -52,8 +54,8 @@ class PatriciaTrieReadingUtils {
     /**
      * Node Flags
      */
-    static AK_FORCE_INLINE bool isBlacklisted(const NodeFlags flags) {
-        return (flags & FLAG_IS_BLACKLISTED) != 0;
+    static AK_FORCE_INLINE bool isPossiblyOffensive(const NodeFlags flags) {
+        return (flags & FLAG_IS_POSSIBLY_OFFENSIVE) != 0;
     }
 
     static AK_FORCE_INLINE bool isNotAWord(const NodeFlags flags) {
@@ -80,12 +82,12 @@ class PatriciaTrieReadingUtils {
         return FLAG_CHILDREN_POSITION_TYPE_NOPOSITION != (MASK_CHILDREN_POSITION_TYPE & flags);
     }
 
-    static AK_FORCE_INLINE NodeFlags createAndGetFlags(const bool isBlacklisted,
+    static AK_FORCE_INLINE NodeFlags createAndGetFlags(const bool isPossiblyOffensive,
             const bool isNotAWord, const bool isTerminal, const bool hasShortcutTargets,
             const bool hasBigrams, const bool hasMultipleChars,
             const int childrenPositionFieldSize) {
         NodeFlags nodeFlags = 0;
-        nodeFlags = isBlacklisted ? (nodeFlags | FLAG_IS_BLACKLISTED) : nodeFlags;
+        nodeFlags = isPossiblyOffensive ? (nodeFlags | FLAG_IS_POSSIBLY_OFFENSIVE) : nodeFlags;
         nodeFlags = isNotAWord ? (nodeFlags | FLAG_IS_NOT_A_WORD) : nodeFlags;
         nodeFlags = isTerminal ? (nodeFlags | FLAG_IS_TERMINAL) : nodeFlags;
         nodeFlags = hasShortcutTargets ? (nodeFlags | FLAG_HAS_SHORTCUT_TARGETS) : nodeFlags;
@@ -106,9 +108,10 @@ class PatriciaTrieReadingUtils {
     static void readPtNodeInfo(const uint8_t *const dictBuf, const int ptNodePos,
             const DictionaryShortcutsStructurePolicy *const shortcutPolicy,
             const DictionaryBigramsStructurePolicy *const bigramPolicy,
-            NodeFlags *const outFlags, int *const outCodePointCount, int *const outCodePoint,
-            int *const outProbability, int *const outChildrenPos, int *const outShortcutPos,
-            int *const outBigramPos, int *const outSiblingPos);
+            const int *const codePointTable, NodeFlags *const outFlags,
+            int *const outCodePointCount, int *const outCodePoint, int *const outProbability,
+            int *const outChildrenPos, int *const outShortcutPos, int *const outBigramPos,
+            int *const outSiblingPos);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(PatriciaTrieReadingUtils);
@@ -124,7 +127,7 @@ class PatriciaTrieReadingUtils {
     static const NodeFlags FLAG_HAS_SHORTCUT_TARGETS;
     static const NodeFlags FLAG_HAS_BIGRAMS;
     static const NodeFlags FLAG_IS_NOT_A_WORD;
-    static const NodeFlags FLAG_IS_BLACKLISTED;
+    static const NodeFlags FLAG_IS_POSSIBLY_OFFENSIVE;
 };
 } // namespace latinime
 #endif /* LATINIME_PATRICIA_TRIE_NODE_READING_UTILS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h b/native/jni/src/dictionary/structure/pt_common/pt_node_array_reader.h
index 6078d8285..6078d8285 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h
+++ b/native/jni/src/dictionary/structure/pt_common/pt_node_array_reader.h
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h b/native/jni/src/dictionary/structure/pt_common/pt_node_params.h
index b2e60a837..905deb1bc 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h
+++ b/native/jni/src/dictionary/structure/pt_common/pt_node_params.h
@@ -20,10 +20,11 @@
 #include <cstring>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
 #include "utils/char_utils.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -88,9 +89,9 @@ class PtNodeParams {
     // Construct new params by updating existing PtNode params.
     PtNodeParams(const PtNodeParams *const ptNodeParams,
             const PatriciaTrieReadingUtils::NodeFlags flags, const int parentPos,
-            const int codePointCount, const int *const codePoints, const int probability)
+            const CodePointArrayView codePoints, const int probability)
             : mHeadPos(ptNodeParams->getHeadPos()), mFlags(flags), mHasMovedFlag(true),
-              mParentPos(parentPos), mCodePointCount(codePointCount), mCodePoints(),
+              mParentPos(parentPos), mCodePointCount(codePoints.size()), mCodePoints(),
               mTerminalIdFieldPos(ptNodeParams->getTerminalIdFieldPos()),
               mTerminalId(ptNodeParams->getTerminalId()),
               mProbabilityFieldPos(ptNodeParams->getProbabilityFieldPos()),
@@ -101,20 +102,20 @@ class PtNodeParams {
               mShortcutPos(ptNodeParams->getShortcutPos()),
               mBigramPos(ptNodeParams->getBigramsPos()),
               mSiblingPos(ptNodeParams->getSiblingNodePos()) {
-        memcpy(mCodePoints, codePoints, sizeof(int) * mCodePointCount);
+        memcpy(mCodePoints, codePoints.data(), sizeof(int) * mCodePointCount);
     }
 
     PtNodeParams(const PatriciaTrieReadingUtils::NodeFlags flags, const int parentPos,
-            const int codePointCount, const int *const codePoints, const int probability)
+            const CodePointArrayView codePoints, const int probability)
             : mHeadPos(NOT_A_DICT_POS), mFlags(flags), mHasMovedFlag(true), mParentPos(parentPos),
-              mCodePointCount(codePointCount), mCodePoints(),
+              mCodePointCount(codePoints.size()), mCodePoints(),
               mTerminalIdFieldPos(NOT_A_DICT_POS),
               mTerminalId(Ver4DictConstants::NOT_A_TERMINAL_ID),
               mProbabilityFieldPos(NOT_A_DICT_POS), mProbability(probability),
               mChildrenPosFieldPos(NOT_A_DICT_POS), mChildrenPos(NOT_A_DICT_POS),
               mBigramLinkedNodePos(NOT_A_DICT_POS), mShortcutPos(NOT_A_DICT_POS),
               mBigramPos(NOT_A_DICT_POS), mSiblingPos(NOT_A_DICT_POS) {
-        memcpy(mCodePoints, codePoints, sizeof(int) * mCodePointCount);
+        memcpy(mCodePoints, codePoints.data(), sizeof(int) * mCodePointCount);
     }
 
     AK_FORCE_INLINE bool isValid() const {
@@ -143,8 +144,8 @@ class PtNodeParams {
         return PatriciaTrieReadingUtils::isTerminal(mFlags);
     }
 
-    AK_FORCE_INLINE bool isBlacklisted() const {
-        return PatriciaTrieReadingUtils::isBlacklisted(mFlags);
+    AK_FORCE_INLINE bool isPossiblyOffensive() const {
+        return PatriciaTrieReadingUtils::isPossiblyOffensive(mFlags);
     }
 
     AK_FORCE_INLINE bool isNotAWord() const {
@@ -174,11 +175,17 @@ class PtNodeParams {
         return mParentPos;
     }
 
+    AK_FORCE_INLINE const CodePointArrayView getCodePointArrayView() const {
+        return CodePointArrayView(mCodePoints, mCodePointCount);
+    }
+
+    // TODO: Remove
     // Number of code points
     AK_FORCE_INLINE uint8_t getCodePointCount() const {
         return mCodePointCount;
     }
 
+    // TODO: Remove
     AK_FORCE_INLINE const int *getCodePoints() const {
         return mCodePoints;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h b/native/jni/src/dictionary/structure/pt_common/pt_node_reader.h
index 31299a707..15da19e0b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h
+++ b/native/jni/src/dictionary/structure/pt_common/pt_node_reader.h
@@ -19,7 +19,7 @@
 
 #include "defines.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h b/native/jni/src/dictionary/structure/pt_common/pt_node_writer.h
index 955d779ac..e6cad25aa 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h
+++ b/native/jni/src/dictionary/structure/pt_common/pt_node_writer.h
@@ -20,12 +20,12 @@
 #include <unordered_map>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
 #include "utils/int_array_view.h"
 
 namespace latinime {
 
-class BigramProperty;
+class NgramProperty;
 class UnigramProperty;
 
 // Interface class used to write PtNode information.
@@ -72,7 +72,7 @@ class PtNodeWriter {
             const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos) = 0;
 
     virtual bool addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) = 0;
+            const NgramProperty *const ngramProperty, bool *const outAddedNewEntry) = 0;
 
     virtual bool removeNgramEntry(const WordIdArrayView prevWordIds, const int wordId) = 0;
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.cpp b/native/jni/src/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.cpp
index 91c76941c..14428edd4 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.cpp
+++ b/native/jni/src/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
@@ -31,21 +31,23 @@ const int ShortcutListReadingUtils::SHORTCUT_LIST_SIZE_FIELD_SIZE = 2;
 const int ShortcutListReadingUtils::WHITELIST_SHORTCUT_PROBABILITY = 15;
 
 /* static */ ShortcutListReadingUtils::ShortcutFlags
-        ShortcutListReadingUtils::getFlagsAndForwardPointer(const uint8_t *const dictRoot,
+        ShortcutListReadingUtils::getFlagsAndForwardPointer(const ReadOnlyByteArrayView buffer,
                 int *const pos) {
-    return ByteArrayUtils::readUint8AndAdvancePosition(dictRoot, pos);
+    return ByteArrayUtils::readUint8AndAdvancePosition(buffer.data(), pos);
 }
 
 /* static */ int ShortcutListReadingUtils::getShortcutListSizeAndForwardPointer(
-        const uint8_t *const dictRoot, int *const pos) {
+        const ReadOnlyByteArrayView buffer, int *const pos) {
     // readUint16andAdvancePosition() returns an offset *including* the uint16 field itself.
-    return ByteArrayUtils::readUint16AndAdvancePosition(dictRoot, pos)
+    return ByteArrayUtils::readUint16AndAdvancePosition(buffer.data(), pos)
             - SHORTCUT_LIST_SIZE_FIELD_SIZE;
 }
 
-/* static */ int ShortcutListReadingUtils::readShortcutTarget(
-        const uint8_t *const dictRoot, const int maxLength, int *const outWord, int *const pos) {
-    return ByteArrayUtils::readStringAndAdvancePosition(dictRoot, maxLength, outWord, pos);
+/* static */ int ShortcutListReadingUtils::readShortcutTarget(const ReadOnlyByteArrayView buffer,
+        const int maxLength, int *const outWord, int *const pos) {
+    // TODO: Use codePointTable for shortcuts.
+    return ByteArrayUtils::readStringAndAdvancePosition(buffer.data(), maxLength,
+            nullptr /* codePointTable */, outWord, pos);
 }
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h b/native/jni/src/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h
index d065bf7fd..71cb8cc2c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h
+++ b/native/jni/src/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h
@@ -20,6 +20,7 @@
 #include <cstdint>
 
 #include "defines.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
@@ -27,7 +28,8 @@ class ShortcutListReadingUtils {
  public:
     typedef uint8_t ShortcutFlags;
 
-    static ShortcutFlags getFlagsAndForwardPointer(const uint8_t *const dictRoot, int *const pos);
+    static ShortcutFlags getFlagsAndForwardPointer(const ReadOnlyByteArrayView buffer,
+            int *const pos);
 
     static AK_FORCE_INLINE int getProbabilityFromFlags(const ShortcutFlags flags) {
         return flags & MASK_ATTRIBUTE_PROBABILITY;
@@ -39,14 +41,15 @@ class ShortcutListReadingUtils {
 
     // This method returns the size of the shortcut list region excluding the shortcut list size
     // field at the beginning.
-    static int getShortcutListSizeAndForwardPointer(const uint8_t *const dictRoot, int *const pos);
+    static int getShortcutListSizeAndForwardPointer(const ReadOnlyByteArrayView buffer,
+            int *const pos);
 
     static AK_FORCE_INLINE int getShortcutListSizeFieldSize() {
         return SHORTCUT_LIST_SIZE_FIELD_SIZE;
     }
 
-    static AK_FORCE_INLINE void skipShortcuts(const uint8_t *const dictRoot, int *const pos) {
-        const int shortcutListSize = getShortcutListSizeAndForwardPointer(dictRoot, pos);
+    static AK_FORCE_INLINE void skipShortcuts(const ReadOnlyByteArrayView buffer, int *const pos) {
+        const int shortcutListSize = getShortcutListSizeAndForwardPointer(buffer, pos);
         *pos += shortcutListSize;
     }
 
@@ -54,7 +57,7 @@ class ShortcutListReadingUtils {
         return getProbabilityFromFlags(flags) == WHITELIST_SHORTCUT_PROBABILITY;
     }
 
-    static int readShortcutTarget(const uint8_t *const dictRoot, const int maxLength,
+    static int readShortcutTarget(const ReadOnlyByteArrayView buffer, const int maxLength,
             int *const outWord, int *const pos);
 
  private:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/bigram/bigram_list_policy.h b/native/jni/src/dictionary/structure/v2/bigram/bigram_list_policy.h
index 73e291ec2..25081fa04 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/bigram/bigram_list_policy.h
+++ b/native/jni/src/dictionary/structure/v2/bigram/bigram_list_policy.h
@@ -20,24 +20,24 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
+#include "dictionary/interface/dictionary_bigrams_structure_policy.h"
+#include "dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
 class BigramListPolicy : public DictionaryBigramsStructurePolicy {
  public:
-    BigramListPolicy(const uint8_t *const bigramsBuf, const int bufSize)
-            : mBigramsBuf(bigramsBuf), mBufSize(bufSize) {}
+    BigramListPolicy(const ReadOnlyByteArrayView buffer) : mBuffer(buffer) {}
 
     ~BigramListPolicy() {}
 
     void getNextBigram(int *const outBigramPos, int *const outProbability, bool *const outHasNext,
             int *const pos) const {
         BigramListReadWriteUtils::BigramFlags flags;
-        if (!BigramListReadWriteUtils::getBigramEntryPropertiesAndAdvancePosition(mBigramsBuf,
-                mBufSize, &flags, outBigramPos, pos)) {
-            AKLOGE("Cannot read bigram entry. mBufSize: %d, pos: %d. ", mBufSize, *pos);
+        if (!BigramListReadWriteUtils::getBigramEntryPropertiesAndAdvancePosition(mBuffer, &flags,
+                outBigramPos, pos)) {
+            AKLOGE("Cannot read bigram entry. bufSize: %zd, pos: %d. ", mBuffer.size(), *pos);
             *outProbability = NOT_A_PROBABILITY;
             *outHasNext = false;
             return;
@@ -47,14 +47,13 @@ class BigramListPolicy : public DictionaryBigramsStructurePolicy {
     }
 
     bool skipAllBigrams(int *const pos) const {
-        return BigramListReadWriteUtils::skipExistingBigrams(mBigramsBuf, mBufSize, pos);
+        return BigramListReadWriteUtils::skipExistingBigrams(mBuffer, pos);
     }
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(BigramListPolicy);
 
-    const uint8_t *const mBigramsBuf;
-    const int mBufSize;
+    const ReadOnlyByteArrayView mBuffer;
 };
 } // namespace latinime
 #endif // LATINIME_BIGRAM_LIST_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp b/native/jni/src/dictionary/structure/v2/patricia_trie_policy.cpp
index ea32eb2a9..4e8b96b08 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp
+++ b/native/jni/src/dictionary/structure/v2/patricia_trie_policy.cpp
@@ -14,18 +14,18 @@
  * limitations under the License.
  */
 
-
-#include "suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h"
+#include "dictionary/structure/v2/patricia_trie_policy.h"
 
 #include "defines.h"
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_vector.h"
-#include "suggest/core/dictionary/binary_dictionary_bigrams_iterator.h"
-#include "suggest/core/dictionary/ngram_listener.h"
-#include "suggest/core/session/prev_words_info.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/probability_utils.h"
+#include "dictionary/interface/ngram_listener.h"
+#include "dictionary/property/ngram_context.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/utils/binary_dictionary_bigrams_iterator.h"
+#include "dictionary/utils/multi_bigram_map.h"
+#include "dictionary/utils/probability_utils.h"
 #include "utils/char_utils.h"
 
 namespace latinime {
@@ -36,19 +36,19 @@ void PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNo
         return;
     }
     int nextPos = dicNode->getChildrenPtNodeArrayPos();
-    if (nextPos < 0 || nextPos >= mDictBufferSize) {
-        AKLOGE("Children PtNode array position is invalid. pos: %d, dict size: %d",
-                nextPos, mDictBufferSize);
+    if (!isValidPos(nextPos)) {
+        AKLOGE("Children PtNode array position is invalid. pos: %d, dict size: %zd",
+                nextPos, mBuffer.size());
         mIsCorrupted = true;
         ASSERT(false);
         return;
     }
     const int childCount = PatriciaTrieReadingUtils::getPtNodeArraySizeAndAdvancePosition(
-            mDictRoot, &nextPos);
+            mBuffer.data(), &nextPos);
     for (int i = 0; i < childCount; i++) {
-        if (nextPos < 0 || nextPos >= mDictBufferSize) {
-            AKLOGE("Child PtNode position is invalid. pos: %d, dict size: %d, childCount: %d / %d",
-                    nextPos, mDictBufferSize, i, childCount);
+        if (!isValidPos(nextPos)) {
+            AKLOGE("Child PtNode position is invalid. pos: %d, dict size: %zd, childCount: %d / %d",
+                    nextPos, mBuffer.size(), i, childCount);
             mIsCorrupted = true;
             ASSERT(false);
             return;
@@ -57,7 +57,12 @@ void PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNo
     }
 }
 
-// This retrieves code points and the probability of the word by its terminal position.
+int PatriciaTriePolicy::getCodePointsAndReturnCodePointCount(const int wordId,
+        const int maxCodePointCount, int *const outCodePoints) const {
+    return getCodePointsAndProbabilityAndReturnCodePointCount(wordId, maxCodePointCount,
+            outCodePoints, nullptr /* outUnigramProbability */);
+}
+// This retrieves code points and the probability of the word by its id.
 // Due to the fact that words are ordered in the dictionary in a strict breadth-first order,
 // it is possible to check for this with advantageous complexity. For each PtNode array, we search
 // for PtNodes with children and compare the children position with the position we look for.
@@ -68,18 +73,22 @@ void PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNo
 // with a z, it's the last PtNode of the root array, so all children addresses will be smaller
 // than the position we look for, and we have to descend the z PtNode).
 /* Parameters :
- * ptNodePos: the byte position of the terminal PtNode of the word we are searching for (this is
- *   what is stored as the "bigram position" in each bigram)
+ * wordId: Id of the word we are searching for.
  * outCodePoints: an array to write the found word, with MAX_WORD_LENGTH size.
  * outUnigramProbability: a pointer to an int to write the probability into.
  * Return value : the code point count, of 0 if the word was not found.
  */
 // TODO: Split this function to be more readable
 int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
-        const int ptNodePos, const int maxCodePointCount, int *const outCodePoints,
+        const int wordId, const int maxCodePointCount, int *const outCodePoints,
         int *const outUnigramProbability) const {
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
     int pos = getRootPosition();
     int wordPos = 0;
+    const int *const codePointTable = mHeaderPolicy.getCodePointTable();
+    if (outUnigramProbability) {
+        *outUnigramProbability = NOT_A_PROBABILITY;
+    }
     // One iteration of the outer loop iterates through PtNode arrays. As stated above, we will
     // only traverse PtNodes that are actually a part of the terminal we are searching, so each
     // time we enter this loop we are one depth level further than last time.
@@ -90,56 +99,57 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
         int lastCandidatePtNodePos = 0;
         // Let's loop through PtNodes in this PtNode array searching for either the terminal
         // or one of its ascendants.
-        if (pos < 0 || pos >= mDictBufferSize) {
-            AKLOGE("PtNode array position is invalid. pos: %d, dict size: %d",
-                    pos, mDictBufferSize);
+        if (!isValidPos(pos)) {
+            AKLOGE("PtNode array position is invalid. pos: %d, dict size: %zd",
+                    pos, mBuffer.size());
             mIsCorrupted = true;
             ASSERT(false);
-            *outUnigramProbability = NOT_A_PROBABILITY;
             return 0;
         }
         for (int ptNodeCount = PatriciaTrieReadingUtils::getPtNodeArraySizeAndAdvancePosition(
-                mDictRoot, &pos); ptNodeCount > 0; --ptNodeCount) {
+                mBuffer.data(), &pos); ptNodeCount > 0; --ptNodeCount) {
             const int startPos = pos;
-            if (pos < 0 || pos >= mDictBufferSize) {
-                AKLOGE("PtNode position is invalid. pos: %d, dict size: %d", pos, mDictBufferSize);
+            if (!isValidPos(pos)) {
+                AKLOGE("PtNode position is invalid. pos: %d, dict size: %zd", pos, mBuffer.size());
                 mIsCorrupted = true;
                 ASSERT(false);
-                *outUnigramProbability = NOT_A_PROBABILITY;
                 return 0;
             }
             const PatriciaTrieReadingUtils::NodeFlags flags =
-                    PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(mDictRoot, &pos);
+                    PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(mBuffer.data(), &pos);
             const int character = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                    mDictRoot, &pos);
+                    mBuffer.data(), codePointTable, &pos);
             if (ptNodePos == startPos) {
                 // We found the position. Copy the rest of the code points in the buffer and return
                 // the length.
                 outCodePoints[wordPos] = character;
                 if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
                     int nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                            mDictRoot, &pos);
+                            mBuffer.data(), codePointTable, &pos);
                     // We count code points in order to avoid infinite loops if the file is broken
                     // or if there is some other bug
                     int charCount = maxCodePointCount;
                     while (NOT_A_CODE_POINT != nextChar && --charCount > 0) {
                         outCodePoints[++wordPos] = nextChar;
                         nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                                mDictRoot, &pos);
+                                mBuffer.data(), codePointTable, &pos);
                     }
                 }
-                *outUnigramProbability =
-                        PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot,
-                                &pos);
+                if (outUnigramProbability) {
+                    *outUnigramProbability =
+                            PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(
+                                    mBuffer.data(), &pos);
+                }
                 return ++wordPos;
             }
             // We need to skip past this PtNode, so skip any remaining code points after the
             // first and possibly the probability.
             if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
-                PatriciaTrieReadingUtils::skipCharacters(mDictRoot, flags, MAX_WORD_LENGTH, &pos);
+                PatriciaTrieReadingUtils::skipCharacters(mBuffer.data(), flags, MAX_WORD_LENGTH,
+                        codePointTable, &pos);
             }
             if (PatriciaTrieReadingUtils::isTerminal(flags)) {
-                PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot, &pos);
+                PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mBuffer.data(), &pos);
             }
             // The fact that this PtNode has children is very important. Since we already know
             // that this PtNode does not match, if it has no children we know it is irrelevant
@@ -154,7 +164,8 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
                 int currentPos = pos;
                 // Here comes the tricky part. First, read the children position.
                 const int childrenPos = PatriciaTrieReadingUtils
-                        ::readChildrenPositionAndAdvancePosition(mDictRoot, flags, &currentPos);
+                        ::readChildrenPositionAndAdvancePosition(mBuffer.data(), flags,
+                                &currentPos);
                 if (childrenPos > ptNodePos) {
                     // If the children pos is greater than the position, it means the previous
                     // PtNode, which position is stored in lastCandidatePtNodePos, was the right
@@ -184,30 +195,30 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
                 if (0 != lastCandidatePtNodePos) {
                     const PatriciaTrieReadingUtils::NodeFlags lastFlags =
                             PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(
-                                    mDictRoot, &lastCandidatePtNodePos);
+                                    mBuffer.data(), &lastCandidatePtNodePos);
                     const int lastChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                            mDictRoot, &lastCandidatePtNodePos);
+                            mBuffer.data(), codePointTable, &lastCandidatePtNodePos);
                     // We copy all the characters in this PtNode to the buffer
                     outCodePoints[wordPos] = lastChar;
                     if (PatriciaTrieReadingUtils::hasMultipleChars(lastFlags)) {
                         int nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                                mDictRoot, &lastCandidatePtNodePos);
+                                mBuffer.data(), codePointTable, &lastCandidatePtNodePos);
                         int charCount = maxCodePointCount;
                         while (-1 != nextChar && --charCount > 0) {
                             outCodePoints[++wordPos] = nextChar;
                             nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
-                                    mDictRoot, &lastCandidatePtNodePos);
+                                    mBuffer.data(), codePointTable, &lastCandidatePtNodePos);
                         }
                     }
                     ++wordPos;
                     // Now we only need to branch to the children address. Skip the probability if
                     // it's there, read pos, and break to resume the search at pos.
                     if (PatriciaTrieReadingUtils::isTerminal(lastFlags)) {
-                        PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot,
+                        PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mBuffer.data(),
                                 &lastCandidatePtNodePos);
                     }
                     pos = PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
-                            mDictRoot, lastFlags, &lastCandidatePtNodePos);
+                            mBuffer.data(), lastFlags, &lastCandidatePtNodePos);
                     break;
                 } else {
                     // Here is a little tricky part: we come here if we found out that all children
@@ -219,18 +230,17 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
                     // ready to start the next one.
                     if (PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
                         PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
-                                mDictRoot, flags, &pos);
+                                mBuffer.data(), flags, &pos);
                     }
                     if (PatriciaTrieReadingUtils::hasShortcutTargets(flags)) {
                         mShortcutListPolicy.skipAllShortcuts(&pos);
                     }
                     if (PatriciaTrieReadingUtils::hasBigrams(flags)) {
                         if (!mBigramListPolicy.skipAllBigrams(&pos)) {
-                            AKLOGE("Cannot skip bigrams. BufSize: %d, pos: %d.", mDictBufferSize,
+                            AKLOGE("Cannot skip bigrams. BufSize: %zd, pos: %d.", mBuffer.size(),
                                     pos);
                             mIsCorrupted = true;
                             ASSERT(false);
-                            *outUnigramProbability = NOT_A_PROBABILITY;
                             return 0;
                         }
                     }
@@ -243,17 +253,16 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
                 // our pos is after the end of this PtNode, at the start of the next one.
                 if (PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
                     PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
-                            mDictRoot, flags, &pos);
+                            mBuffer.data(), flags, &pos);
                 }
                 if (PatriciaTrieReadingUtils::hasShortcutTargets(flags)) {
                     mShortcutListPolicy.skipAllShortcuts(&pos);
                 }
                 if (PatriciaTrieReadingUtils::hasBigrams(flags)) {
                     if (!mBigramListPolicy.skipAllBigrams(&pos)) {
-                        AKLOGE("Cannot skip bigrams. BufSize: %d, pos: %d.", mDictBufferSize, pos);
+                        AKLOGE("Cannot skip bigrams. BufSize: %zd, pos: %d.", mBuffer.size(), pos);
                         mIsCorrupted = true;
                         ASSERT(false);
-                        *outUnigramProbability = NOT_A_PROBABILITY;
                         return 0;
                     }
                 }
@@ -267,18 +276,48 @@ int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
 }
 
 // This function gets the position of the terminal PtNode of the exact matching word in the
-// dictionary. If no match is found, it returns NOT_A_DICT_POS.
-int PatriciaTriePolicy::getTerminalPtNodePositionOfWord(const int *const inWord,
-        const int length, const bool forceLowerCaseSearch) const {
+// dictionary. If no match is found, it returns NOT_A_WORD_ID.
+int PatriciaTriePolicy::getWordId(const CodePointArrayView wordCodePoints,
+        const bool forceLowerCaseSearch) const {
     DynamicPtReadingHelper readingHelper(&mPtNodeReader, &mPtNodeArrayReader);
     readingHelper.initWithPtNodeArrayPos(getRootPosition());
-    const int ptNodePos =
-            readingHelper.getTerminalPtNodePositionOfWord(inWord, length, forceLowerCaseSearch);
+    const int ptNodePos = readingHelper.getTerminalPtNodePositionOfWord(wordCodePoints.data(),
+            wordCodePoints.size(), forceLowerCaseSearch);
     if (readingHelper.isError()) {
         mIsCorrupted = true;
-        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+        AKLOGE("Dictionary reading error in getWordId().");
+    }
+    return getWordIdFromTerminalPtNodePos(ptNodePos);
+}
+
+const WordAttributes PatriciaTriePolicy::getWordAttributesInContext(
+        const WordIdArrayView prevWordIds, const int wordId,
+        MultiBigramMap *const multiBigramMap) const {
+    if (wordId == NOT_A_WORD_ID) {
+        return WordAttributes();
+    }
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
+    const PtNodeParams ptNodeParams =
+            mPtNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
+    if (multiBigramMap) {
+        const int probability =  multiBigramMap->getBigramProbability(this /* structurePolicy */,
+                prevWordIds, wordId, ptNodeParams.getProbability());
+        return getWordAttributes(probability, ptNodeParams);
+    }
+    if (!prevWordIds.empty()) {
+        const int bigramProbability = getProbabilityOfWord(prevWordIds, wordId);
+        if (bigramProbability != NOT_A_PROBABILITY) {
+            return getWordAttributes(bigramProbability, ptNodeParams);
+        }
     }
-    return ptNodePos;
+    return getWordAttributes(getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY),
+            ptNodeParams);
+}
+
+const WordAttributes PatriciaTriePolicy::getWordAttributes(const int probability,
+        const PtNodeParams &ptNodeParams) const {
+    return WordAttributes(probability, false /* isBlacklisted */, ptNodeParams.isNotAWord(),
+            ptNodeParams.isPossiblyOffensive());
 }
 
 int PatriciaTriePolicy::getProbability(const int unigramProbability,
@@ -297,21 +336,22 @@ int PatriciaTriePolicy::getProbability(const int unigramProbability,
     }
 }
 
-int PatriciaTriePolicy::getProbabilityOfPtNode(const int *const prevWordsPtNodePos,
-        const int ptNodePos) const {
-    if (ptNodePos == NOT_A_DICT_POS) {
+int PatriciaTriePolicy::getProbabilityOfWord(const WordIdArrayView prevWordIds,
+        const int wordId) const {
+    if (wordId == NOT_A_WORD_ID) {
         return NOT_A_PROBABILITY;
     }
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
     const PtNodeParams ptNodeParams =
             mPtNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-    if (ptNodeParams.isNotAWord() || ptNodeParams.isBlacklisted()) {
-        // If this is not a word, or if it's a blacklisted entry, it should behave as
-        // having no probability outside of the suggestion process (where it should be used
-        // for shortcuts).
+    if (ptNodeParams.isNotAWord()) {
+        // If this is not a word, it should behave as having no probability outside of the
+        // suggestion process (where it should be used for shortcuts).
         return NOT_A_PROBABILITY;
     }
-    if (prevWordsPtNodePos) {
-        const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
+    if (!prevWordIds.empty()) {
+        const int bigramsPosition = getBigramsPositionOfPtNode(
+                getTerminalPtNodePosFromWordId(prevWordIds[0]));
         BinaryDictionaryBigramsIterator bigramsIt(&mBigramListPolicy, bigramsPosition);
         while (bigramsIt.hasNext()) {
             bigramsIt.next();
@@ -325,19 +365,26 @@ int PatriciaTriePolicy::getProbabilityOfPtNode(const int *const prevWordsPtNodeP
     return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
 }
 
-void PatriciaTriePolicy::iterateNgramEntries(const int *const prevWordsPtNodePos,
+void PatriciaTriePolicy::iterateNgramEntries(const WordIdArrayView prevWordIds,
         NgramListener *const listener) const {
-    if (!prevWordsPtNodePos) {
+    if (prevWordIds.empty()) {
         return;
     }
-    const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
+    const int bigramsPosition = getBigramsPositionOfPtNode(
+            getTerminalPtNodePosFromWordId(prevWordIds[0]));
     BinaryDictionaryBigramsIterator bigramsIt(&mBigramListPolicy, bigramsPosition);
     while (bigramsIt.hasNext()) {
         bigramsIt.next();
-        listener->onVisitEntry(bigramsIt.getProbability(), bigramsIt.getBigramPos());
+        listener->onVisitEntry(bigramsIt.getProbability(),
+                getWordIdFromTerminalPtNodePos(bigramsIt.getBigramPos()));
     }
 }
 
+BinaryDictionaryShortcutIterator PatriciaTriePolicy::getShortcutIterator(const int wordId) const {
+    const int shortcutPos = getShortcutPositionOfPtNode(getTerminalPtNodePosFromWordId(wordId));
+    return BinaryDictionaryShortcutIterator(&mShortcutListPolicy, shortcutPos);
+}
+
 int PatriciaTriePolicy::getShortcutPositionOfPtNode(const int ptNodePos) const {
     if (ptNodePos == NOT_A_DICT_POS) {
         return NOT_A_DICT_POS;
@@ -362,35 +409,32 @@ int PatriciaTriePolicy::createAndGetLeavingChildNode(const DicNode *const dicNod
     int shortcutPos = NOT_A_DICT_POS;
     int bigramPos = NOT_A_DICT_POS;
     int siblingPos = NOT_A_DICT_POS;
-    PatriciaTrieReadingUtils::readPtNodeInfo(mDictRoot, ptNodePos, getShortcutsStructurePolicy(),
-            &mBigramListPolicy, &flags, &mergedNodeCodePointCount, mergedNodeCodePoints,
-            &probability, &childrenPos, &shortcutPos, &bigramPos, &siblingPos);
+    const int *const codePointTable = mHeaderPolicy.getCodePointTable();
+    PatriciaTrieReadingUtils::readPtNodeInfo(mBuffer.data(), ptNodePos, &mShortcutListPolicy,
+            &mBigramListPolicy, codePointTable, &flags, &mergedNodeCodePointCount,
+            mergedNodeCodePoints, &probability, &childrenPos, &shortcutPos, &bigramPos,
+            &siblingPos);
     // Skip PtNodes don't start with Unicode code point because they represent non-word information.
     if (CharUtils::isInUnicodeSpace(mergedNodeCodePoints[0])) {
-        childDicNodes->pushLeavingChild(dicNode, ptNodePos, childrenPos, probability,
-                PatriciaTrieReadingUtils::isTerminal(flags),
-                PatriciaTrieReadingUtils::hasChildrenInFlags(flags),
-                PatriciaTrieReadingUtils::isBlacklisted(flags)
-                        || PatriciaTrieReadingUtils::isNotAWord(flags),
-                mergedNodeCodePointCount, mergedNodeCodePoints);
+        const int wordId = PatriciaTrieReadingUtils::isTerminal(flags) ? ptNodePos : NOT_A_WORD_ID;
+        childDicNodes->pushLeavingChild(dicNode, childrenPos, wordId,
+                CodePointArrayView(mergedNodeCodePoints, mergedNodeCodePointCount));
     }
     return siblingPos;
 }
 
-const WordProperty PatriciaTriePolicy::getWordProperty(const int *const codePoints,
-        const int codePointCount) const {
-    const int ptNodePos = getTerminalPtNodePositionOfWord(codePoints, codePointCount,
-            false /* forceLowerCaseSearch */);
-    if (ptNodePos == NOT_A_DICT_POS) {
+const WordProperty PatriciaTriePolicy::getWordProperty(
+        const CodePointArrayView wordCodePoints) const {
+    const int wordId = getWordId(wordCodePoints, false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
         AKLOGE("getWordProperty was called for invalid word.");
         return WordProperty();
     }
+    const int ptNodePos = getTerminalPtNodePosFromWordId(wordId);
     const PtNodeParams ptNodeParams =
             mPtNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-    std::vector<int> codePointVector(ptNodeParams.getCodePoints(),
-            ptNodeParams.getCodePoints() + ptNodeParams.getCodePointCount());
     // Fetch bigram information.
-    std::vector<BigramProperty> bigrams;
+    std::vector<NgramProperty> ngrams;
     const int bigramListPos = getBigramsPositionOfPtNode(ptNodePos);
     int bigramWord1CodePoints[MAX_WORD_LENGTH];
     BinaryDictionaryBigramsIterator bigramsIt(&mBigramListPolicy, bigramListPos);
@@ -401,13 +445,14 @@ const WordProperty PatriciaTriePolicy::getWordProperty(const int *const codePoin
         if (bigramsIt.getBigramPos() != NOT_A_DICT_POS) {
             int word1Probability = NOT_A_PROBABILITY;
             const int word1CodePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
-                    bigramsIt.getBigramPos(), MAX_WORD_LENGTH, bigramWord1CodePoints,
-                    &word1Probability);
-            const std::vector<int> word1(bigramWord1CodePoints,
-                    bigramWord1CodePoints + word1CodePointCount);
+                    getWordIdFromTerminalPtNodePos(bigramsIt.getBigramPos()), MAX_WORD_LENGTH,
+                    bigramWord1CodePoints, &word1Probability);
             const int probability = getProbability(word1Probability, bigramsIt.getProbability());
-            bigrams.emplace_back(&word1, probability,
-                    NOT_A_TIMESTAMP /* timestamp */, 0 /* level */, 0 /* count */);
+            ngrams.emplace_back(
+                    NgramContext(wordCodePoints.data(), wordCodePoints.size(),
+                            ptNodeParams.representsBeginningOfSentence()),
+                    CodePointArrayView(bigramWord1CodePoints, word1CodePointCount).toVector(),
+                    probability, HistoricalInfo());
         }
     }
     // Fetch shortcut information.
@@ -415,25 +460,25 @@ const WordProperty PatriciaTriePolicy::getWordProperty(const int *const codePoin
     int shortcutPos = getShortcutPositionOfPtNode(ptNodePos);
     if (shortcutPos != NOT_A_DICT_POS) {
         int shortcutTargetCodePoints[MAX_WORD_LENGTH];
-        ShortcutListReadingUtils::getShortcutListSizeAndForwardPointer(mDictRoot, &shortcutPos);
+        ShortcutListReadingUtils::getShortcutListSizeAndForwardPointer(mBuffer, &shortcutPos);
         bool hasNext = true;
         while (hasNext) {
             const ShortcutListReadingUtils::ShortcutFlags shortcutFlags =
-                    ShortcutListReadingUtils::getFlagsAndForwardPointer(mDictRoot, &shortcutPos);
+                    ShortcutListReadingUtils::getFlagsAndForwardPointer(mBuffer, &shortcutPos);
             hasNext = ShortcutListReadingUtils::hasNext(shortcutFlags);
             const int shortcutTargetLength = ShortcutListReadingUtils::readShortcutTarget(
-                    mDictRoot, MAX_WORD_LENGTH, shortcutTargetCodePoints, &shortcutPos);
-            const std::vector<int> shortcutTarget(shortcutTargetCodePoints,
-                    shortcutTargetCodePoints + shortcutTargetLength);
+                    mBuffer, MAX_WORD_LENGTH, shortcutTargetCodePoints, &shortcutPos);
             const int shortcutProbability =
                     ShortcutListReadingUtils::getProbabilityFromFlags(shortcutFlags);
-            shortcuts.emplace_back(&shortcutTarget, shortcutProbability);
+            shortcuts.emplace_back(
+                    CodePointArrayView(shortcutTargetCodePoints, shortcutTargetLength).toVector(),
+                    shortcutProbability);
         }
     }
     const UnigramProperty unigramProperty(ptNodeParams.representsBeginningOfSentence(),
-            ptNodeParams.isNotAWord(), ptNodeParams.isBlacklisted(), ptNodeParams.getProbability(),
-            NOT_A_TIMESTAMP /* timestamp */, 0 /* level */, 0 /* count */, &shortcuts);
-    return WordProperty(&codePointVector, &unigramProperty, &bigrams);
+            ptNodeParams.isNotAWord(), ptNodeParams.isPossiblyOffensive(),
+            ptNodeParams.getProbability(), HistoricalInfo(), std::move(shortcuts));
+    return WordProperty(wordCodePoints.toVector(), unigramProperty, ngrams);
 }
 
 int PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outCodePoints,
@@ -455,9 +500,8 @@ int PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outC
         return 0;
     }
     const int terminalPtNodePos = mTerminalPtNodePositionsForIteratingWords[token];
-    int unigramProbability = NOT_A_PROBABILITY;
-    *outCodePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(terminalPtNodePos,
-            MAX_WORD_LENGTH, outCodePoints, &unigramProbability);
+    *outCodePointCount = getCodePointsAndReturnCodePointCount(
+            getWordIdFromTerminalPtNodePos(terminalPtNodePos), MAX_WORD_LENGTH, outCodePoints);
     const int nextToken = token + 1;
     if (nextToken >= terminalPtNodePositionsVectorSize) {
         // All words have been iterated.
@@ -467,4 +511,16 @@ int PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outC
     return nextToken;
 }
 
+int PatriciaTriePolicy::getWordIdFromTerminalPtNodePos(const int ptNodePos) const {
+    return ptNodePos == NOT_A_DICT_POS ? NOT_A_WORD_ID : ptNodePos;
+}
+
+int PatriciaTriePolicy::getTerminalPtNodePosFromWordId(const int wordId) const {
+    return wordId == NOT_A_WORD_ID ? NOT_A_DICT_POS : wordId;
+}
+
+bool PatriciaTriePolicy::isValidPos(const int pos) const {
+    return pos >= 0 && pos < static_cast<int>(mBuffer.size());
+}
+
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h b/native/jni/src/dictionary/structure/v2/patricia_trie_policy.h
index 70351d147..8edfa7d10 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h
+++ b/native/jni/src/dictionary/structure/v2/patricia_trie_policy.h
@@ -21,35 +21,36 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v2/bigram/bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v2/shortcut/shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/structure/v2/bigram/bigram_list_policy.h"
+#include "dictionary/structure/v2/shortcut/shortcut_list_policy.h"
+#include "dictionary/structure/v2/ver2_patricia_trie_node_reader.h"
+#include "dictionary/structure/v2/ver2_pt_node_array_reader.h"
+#include "dictionary/utils/format_utils.h"
+#include "dictionary/utils/mmapped_buffer.h"
 #include "utils/byte_array_view.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 class DicNode;
 class DicNodeVector;
 
+// Word id = Position of a PtNode that represents the word.
+// Max supported n-gram is bigram.
 class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
  public:
     PatriciaTriePolicy(MmappedBuffer::MmappedBufferPtr mmappedBuffer)
             : mMmappedBuffer(std::move(mmappedBuffer)),
               mHeaderPolicy(mMmappedBuffer->getReadOnlyByteArrayView().data(),
-                      FormatUtils::VERSION_2),
-              mDictRoot(mMmappedBuffer->getReadOnlyByteArrayView().data()
-                      + mHeaderPolicy.getSize()),
-              mDictBufferSize(mMmappedBuffer->getReadOnlyByteArrayView().size()
-                      - mHeaderPolicy.getSize()),
-              mBigramListPolicy(mDictRoot, mDictBufferSize), mShortcutListPolicy(mDictRoot),
-              mPtNodeReader(mDictRoot, mDictBufferSize, &mBigramListPolicy, &mShortcutListPolicy),
-              mPtNodeArrayReader(mDictRoot, mDictBufferSize),
-              mTerminalPtNodePositionsForIteratingWords(), mIsCorrupted(false) {}
+                      FormatUtils::detectFormatVersion(mMmappedBuffer->getReadOnlyByteArrayView())),
+              mBuffer(mMmappedBuffer->getReadOnlyByteArrayView().skip(mHeaderPolicy.getSize())),
+              mBigramListPolicy(mBuffer), mShortcutListPolicy(mBuffer),
+              mPtNodeReader(mBuffer, &mBigramListPolicy, &mShortcutListPolicy,
+                      mHeaderPolicy.getCodePointTable()),
+              mPtNodeArrayReader(mBuffer), mTerminalPtNodePositionsForIteratingWords(),
+              mIsCorrupted(false) {}
 
     AK_FORCE_INLINE int getRootPosition() const {
         return 0;
@@ -58,57 +59,62 @@ class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     void createAndGetAllChildDicNodes(const DicNode *const dicNode,
             DicNodeVector *const childDicNodes) const;
 
-    int getCodePointsAndProbabilityAndReturnCodePointCount(
-            const int terminalNodePos, const int maxCodePointCount, int *const outCodePoints,
-            int *const outUnigramProbability) const;
+    int getCodePointsAndReturnCodePointCount(const int wordId, const int maxCodePointCount,
+            int *const outCodePoints) const;
+
+    int getWordId(const CodePointArrayView wordCodePoints, const bool forceLowerCaseSearch) const;
 
-    int getTerminalPtNodePositionOfWord(const int *const inWord,
-            const int length, const bool forceLowerCaseSearch) const;
+    const WordAttributes getWordAttributesInContext(const WordIdArrayView prevWordIds,
+            const int wordId, MultiBigramMap *const multiBigramMap) const;
 
     int getProbability(const int unigramProbability, const int bigramProbability) const;
 
-    int getProbabilityOfPtNode(const int *const prevWordsPtNodePos, const int ptNodePos) const;
+    int getProbabilityOfWord(const WordIdArrayView prevWordIds, const int wordId) const;
 
-    void iterateNgramEntries(const int *const prevWordsPtNodePos,
+    void iterateNgramEntries(const WordIdArrayView prevWordIds,
             NgramListener *const listener) const;
 
-    int getShortcutPositionOfPtNode(const int ptNodePos) const;
+    BinaryDictionaryShortcutIterator getShortcutIterator(const int wordId) const;
 
     const DictionaryHeaderStructurePolicy *getHeaderStructurePolicy() const {
         return &mHeaderPolicy;
     }
 
-    const DictionaryShortcutsStructurePolicy *getShortcutsStructurePolicy() const {
-        return &mShortcutListPolicy;
-    }
-
-    bool addUnigramEntry(const int *const word, const int length,
+    bool addUnigramEntry(const CodePointArrayView wordCodePoints,
             const UnigramProperty *const unigramProperty) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: addUnigramEntry() is called for non-updatable dictionary.");
         return false;
     }
 
-    bool removeUnigramEntry(const int *const word, const int length) {
+    bool removeUnigramEntry(const CodePointArrayView wordCodePoints) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: removeUnigramEntry() is called for non-updatable dictionary.");
         return false;
     }
 
-    bool addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const BigramProperty *const bigramProperty) {
+    bool addNgramEntry(const NgramProperty *const ngramProperty) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: addNgramEntry() is called for non-updatable dictionary.");
         return false;
     }
 
-    bool removeNgramEntry(const PrevWordsInfo *const prevWordsInfo, const int *const word,
-            const int length) {
+    bool removeNgramEntry(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: removeNgramEntry() is called for non-updatable dictionary.");
         return false;
     }
 
+    bool updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints, const bool isValidWord,
+            const HistoricalInfo historicalInfo) {
+        // This method should not be called for non-updatable dictionary.
+        AKLOGI("Warning: updateEntriesForWordWithNgramContext() is called for non-updatable "
+                "dictionary.");
+        return false;
+    }
+
     bool flush(const char *const filePath) {
         // This method should not be called for non-updatable dictionary.
         AKLOGI("Warning: flush() is called for non-updatable dictionary.");
@@ -135,8 +141,7 @@ class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
         }
     }
 
-    const WordProperty getWordProperty(const int *const codePoints,
-            const int codePointCount) const;
+    const WordProperty getWordProperty(const CodePointArrayView wordCodePoints) const;
 
     int getNextWordAndNextToken(const int token, int *const outCodePoints,
             int *const outCodePointCount);
@@ -150,8 +155,7 @@ class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
 
     const MmappedBuffer::MmappedBufferPtr mMmappedBuffer;
     const HeaderPolicy mHeaderPolicy;
-    const uint8_t *const mDictRoot;
-    const int mDictBufferSize;
+    const ReadOnlyByteArrayView mBuffer;
     const BigramListPolicy mBigramListPolicy;
     const ShortcutListPolicy mShortcutListPolicy;
     const Ver2ParticiaTrieNodeReader mPtNodeReader;
@@ -159,9 +163,18 @@ class PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     std::vector<int> mTerminalPtNodePositionsForIteratingWords;
     mutable bool mIsCorrupted;
 
+    int getCodePointsAndProbabilityAndReturnCodePointCount(const int wordId,
+            const int maxCodePointCount, int *const outCodePoints,
+            int *const outUnigramProbability) const;
+    int getShortcutPositionOfPtNode(const int ptNodePos) const;
     int getBigramsPositionOfPtNode(const int ptNodePos) const;
     int createAndGetLeavingChildNode(const DicNode *const dicNode, const int ptNodePos,
             DicNodeVector *const childDicNodes) const;
+    int getWordIdFromTerminalPtNodePos(const int ptNodePos) const;
+    int getTerminalPtNodePosFromWordId(const int wordId) const;
+    const WordAttributes getWordAttributes(const int probability,
+            const PtNodeParams &ptNodeParams) const;
+    bool isValidPos(const int pos) const;
 };
 } // namespace latinime
 #endif // LATINIME_PATRICIA_TRIE_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/shortcut/shortcut_list_policy.h b/native/jni/src/dictionary/structure/v2/shortcut/shortcut_list_policy.h
index 8e16ccc05..995b1ed01 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/shortcut/shortcut_list_policy.h
+++ b/native/jni/src/dictionary/structure/v2/shortcut/shortcut_list_policy.h
@@ -20,15 +20,15 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "dictionary/interface/dictionary_shortcuts_structure_policy.h"
+#include "dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
 class ShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
  public:
-    explicit ShortcutListPolicy(const uint8_t *const shortcutBuf)
-            : mShortcutsBuf(shortcutBuf) {}
+    explicit ShortcutListPolicy(const ReadOnlyByteArrayView buffer) : mBuffer(buffer) {}
 
     ~ShortcutListPolicy() {}
 
@@ -37,7 +37,7 @@ class ShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
             return NOT_A_DICT_POS;
         }
         int listPos = pos;
-        ShortcutListReadingUtils::getShortcutListSizeAndForwardPointer(mShortcutsBuf, &listPos);
+        ShortcutListReadingUtils::getShortcutListSizeAndForwardPointer(mBuffer, &listPos);
         return listPos;
     }
 
@@ -45,7 +45,7 @@ class ShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
             int *const outCodePointCount, bool *const outIsWhitelist, bool *const outHasNext,
             int *const pos) const {
         const ShortcutListReadingUtils::ShortcutFlags flags =
-                ShortcutListReadingUtils::getFlagsAndForwardPointer(mShortcutsBuf, pos);
+                ShortcutListReadingUtils::getFlagsAndForwardPointer(mBuffer, pos);
         if (outHasNext) {
             *outHasNext = ShortcutListReadingUtils::hasNext(flags);
         }
@@ -54,20 +54,20 @@ class ShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
         }
         if (outCodePoint) {
             *outCodePointCount = ShortcutListReadingUtils::readShortcutTarget(
-                        mShortcutsBuf, maxCodePointCount, outCodePoint, pos);
+                    mBuffer, maxCodePointCount, outCodePoint, pos);
         }
     }
 
     void skipAllShortcuts(int *const pos) const {
         const int shortcutListSize = ShortcutListReadingUtils
-                ::getShortcutListSizeAndForwardPointer(mShortcutsBuf, pos);
+                ::getShortcutListSizeAndForwardPointer(mBuffer, pos);
         *pos += shortcutListSize;
     }
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(ShortcutListPolicy);
 
-    const uint8_t *const mShortcutsBuf;
+    const ReadOnlyByteArrayView mBuffer;
 };
 } // namespace latinime
 #endif // LATINIME_SHORTCUT_LIST_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.cpp b/native/jni/src/dictionary/structure/v2/ver2_patricia_trie_node_reader.cpp
index c1e938710..cbb8ead81 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.cpp
+++ b/native/jni/src/dictionary/structure/v2/ver2_patricia_trie_node_reader.cpp
@@ -14,18 +14,18 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.h"
+#include "dictionary/structure/v2/ver2_patricia_trie_node_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
 
 namespace latinime {
 
 const PtNodeParams Ver2ParticiaTrieNodeReader::fetchPtNodeParamsInBufferFromPtNodePos(
         const int ptNodePos) const {
-    if (ptNodePos < 0 || ptNodePos >= mDictSize) {
+    if (ptNodePos < 0 || ptNodePos >= static_cast<int>(mBuffer.size())) {
         // Reading invalid position because of bug or broken dictionary.
-        AKLOGE("Fetching PtNode info from invalid dictionary position: %d, dictionary size: %d",
-                ptNodePos, mDictSize);
+        AKLOGE("Fetching PtNode info from invalid dictionary position: %d, dictionary size: %zd",
+                ptNodePos, mBuffer.size());
         ASSERT(false);
         return PtNodeParams();
     }
@@ -37,9 +37,9 @@ const PtNodeParams Ver2ParticiaTrieNodeReader::fetchPtNodeParamsInBufferFromPtNo
     int shortcutPos = NOT_A_DICT_POS;
     int bigramPos = NOT_A_DICT_POS;
     int siblingPos = NOT_A_DICT_POS;
-    PatriciaTrieReadingUtils::readPtNodeInfo(mDictBuffer, ptNodePos, mShortuctPolicy,
-            mBigramPolicy, &flags, &mergedNodeCodePointCount, mergedNodeCodePoints, &probability,
-            &childrenPos, &shortcutPos, &bigramPos, &siblingPos);
+    PatriciaTrieReadingUtils::readPtNodeInfo(mBuffer.data(), ptNodePos, mShortcutPolicy,
+            mBigramPolicy, mCodePointTable, &flags, &mergedNodeCodePointCount, mergedNodeCodePoints,
+            &probability, &childrenPos, &shortcutPos, &bigramPos, &siblingPos);
     if (mergedNodeCodePointCount <= 0) {
         AKLOGE("Empty PtNode is not allowed. Code point count: %d", mergedNodeCodePointCount);
         ASSERT(false);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.h b/native/jni/src/dictionary/structure/v2/ver2_patricia_trie_node_reader.h
index f0725b66d..dc87c7c68 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_patricia_trie_node_reader.h
+++ b/native/jni/src/dictionary/structure/v2/ver2_patricia_trie_node_reader.h
@@ -20,8 +20,9 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_reader.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
@@ -30,21 +31,22 @@ class DictionaryShortcutsStructurePolicy;
 
 class Ver2ParticiaTrieNodeReader : public PtNodeReader {
  public:
-    Ver2ParticiaTrieNodeReader(const uint8_t *const dictBuffer, const int dictSize,
+    Ver2ParticiaTrieNodeReader(const ReadOnlyByteArrayView buffer,
             const DictionaryBigramsStructurePolicy *const bigramPolicy,
-            const DictionaryShortcutsStructurePolicy *const shortcutPolicy)
-            : mDictBuffer(dictBuffer), mDictSize(dictSize), mBigramPolicy(bigramPolicy),
-              mShortuctPolicy(shortcutPolicy) {}
+            const DictionaryShortcutsStructurePolicy *const shortcutPolicy,
+            const int *const codePointTable)
+            : mBuffer(buffer), mBigramPolicy(bigramPolicy), mShortcutPolicy(shortcutPolicy),
+              mCodePointTable(codePointTable) {}
 
     virtual const PtNodeParams fetchPtNodeParamsInBufferFromPtNodePos(const int ptNodePos) const;
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(Ver2ParticiaTrieNodeReader);
 
-    const uint8_t *const mDictBuffer;
-    const int mDictSize;
+    const ReadOnlyByteArrayView mBuffer;
     const DictionaryBigramsStructurePolicy *const mBigramPolicy;
-    const DictionaryShortcutsStructurePolicy *const mShortuctPolicy;
+    const DictionaryShortcutsStructurePolicy *const mShortcutPolicy;
+    const int *const mCodePointTable;
 };
 } // namespace latinime
 #endif /* LATINIME_VER2_PATRICIA_TRIE_NODE_READER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.cpp b/native/jni/src/dictionary/structure/v2/ver2_pt_node_array_reader.cpp
index b46617d96..8b9b02df1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.cpp
+++ b/native/jni/src/dictionary/structure/v2/ver2_pt_node_array_reader.cpp
@@ -14,24 +14,24 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.h"
+#include "dictionary/structure/v2/ver2_pt_node_array_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
 
 namespace latinime {
 
 bool Ver2PtNodeArrayReader::readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,
         int *const outPtNodeCount, int *const outFirstPtNodePos) const {
-    if (ptNodeArrayPos < 0 || ptNodeArrayPos >= mDictSize) {
+    if (ptNodeArrayPos < 0 || ptNodeArrayPos >= static_cast<int>(mBuffer.size())) {
         // Reading invalid position because of a bug or a broken dictionary.
-        AKLOGE("Reading PtNode array info from invalid dictionary position: %d, dict size: %d",
-                ptNodeArrayPos, mDictSize);
+        AKLOGE("Reading PtNode array info from invalid dictionary position: %d, dict size: %zd",
+                ptNodeArrayPos, mBuffer.size());
         ASSERT(false);
         return false;
     }
     int readingPos = ptNodeArrayPos;
     const int ptNodeCountInArray = PatriciaTrieReadingUtils::getPtNodeArraySizeAndAdvancePosition(
-            mDictBuffer, &readingPos);
+            mBuffer.data(), &readingPos);
     *outPtNodeCount = ptNodeCountInArray;
     *outFirstPtNodePos = readingPos;
     return true;
@@ -39,10 +39,10 @@ bool Ver2PtNodeArrayReader::readPtNodeArrayInfoAndReturnIfValid(const int ptNode
 
 bool Ver2PtNodeArrayReader::readForwardLinkAndReturnIfValid(const int forwordLinkPos,
         int *const outNextPtNodeArrayPos) const {
-    if (forwordLinkPos < 0 || forwordLinkPos >= mDictSize) {
+    if (forwordLinkPos < 0 || forwordLinkPos >=  static_cast<int>(mBuffer.size())) {
         // Reading invalid position because of bug or broken dictionary.
-        AKLOGE("Reading forward link from invalid dictionary position: %d, dict size: %d",
-                forwordLinkPos, mDictSize);
+        AKLOGE("Reading forward link from invalid dictionary position: %d, dict size: %zd",
+                forwordLinkPos, mBuffer.size());
         ASSERT(false);
         return false;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.h b/native/jni/src/dictionary/structure/v2/ver2_pt_node_array_reader.h
index 548272148..32fa96d15 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/ver2_pt_node_array_reader.h
+++ b/native/jni/src/dictionary/structure/v2/ver2_pt_node_array_reader.h
@@ -20,14 +20,14 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h"
+#include "dictionary/structure/pt_common/pt_node_array_reader.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
 class Ver2PtNodeArrayReader : public PtNodeArrayReader {
  public:
-    Ver2PtNodeArrayReader(const uint8_t *const dictBuffer, const int dictSize)
-            : mDictBuffer(dictBuffer), mDictSize(dictSize) {};
+    Ver2PtNodeArrayReader(const ReadOnlyByteArrayView buffer) : mBuffer(buffer) {};
 
     virtual bool readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,
             int *const outPtNodeCount, int *const outFirstPtNodePos) const;
@@ -37,8 +37,7 @@ class Ver2PtNodeArrayReader : public PtNodeArrayReader {
  private:
     DISALLOW_COPY_AND_ASSIGN(Ver2PtNodeArrayReader);
 
-    const uint8_t *const mDictBuffer;
-    const int mDictSize;
+    const ReadOnlyByteArrayView mBuffer;
 };
 } // namespace latinime
 #endif /* LATINIME_VER2_PT_NODE_ARRAY_READER_H */
diff --git a/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.cpp b/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.cpp
new file mode 100644
index 000000000..165947f87
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.cpp
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/structure/v4/content/dynamic_language_model_probability_utils.h"
+
+namespace latinime {
+
+// Used to provide stable probabilities even if the user's input count is small.
+const int DynamicLanguageModelProbabilityUtils::ASSUMED_MIN_COUNTS[] = {8192, 2, 2, 1};
+
+// Encoded backoff weights.
+// Note that we give positive values for trigrams and quadgrams that means the weight is more than
+// 1.
+// TODO: Apply backoff for main dictionaries and quit giving a positive backoff weight.
+const int DynamicLanguageModelProbabilityUtils::ENCODED_BACKOFF_WEIGHTS[] = {-32, -4, 2, 8};
+
+// This value is used to remove too old entries from the dictionary.
+const int DynamicLanguageModelProbabilityUtils::DURATION_TO_DISCARD_ENTRY_IN_SECONDS =
+        300 * 24 * 60 * 60; // 300 days
+
+} // namespace latinime
diff --git a/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.h b/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.h
new file mode 100644
index 000000000..71824c954
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/dynamic_language_model_probability_utils.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_DYNAMIC_LANGUAGE_MODEL_PROBABILITY_UTILS_H
+#define LATINIME_DYNAMIC_LANGUAGE_MODEL_PROBABILITY_UTILS_H
+
+#include <algorithm>
+
+#include "defines.h"
+#include "dictionary/property/historical_info.h"
+#include "utils/ngram_utils.h"
+#include "utils/time_keeper.h"
+
+namespace latinime {
+
+class DynamicLanguageModelProbabilityUtils {
+ public:
+    static float computeRawProbabilityFromCounts(const int count, const int contextCount,
+            const NgramType ngramType) {
+        const int minCount = ASSUMED_MIN_COUNTS[static_cast<int>(ngramType)];
+        return static_cast<float>(count) / static_cast<float>(std::max(contextCount, minCount));
+    }
+
+    static float backoff(const int ngramProbability, const NgramType ngramType) {
+        const int probability =
+                ngramProbability + ENCODED_BACKOFF_WEIGHTS[static_cast<int>(ngramType)];
+        return std::min(std::max(probability, NOT_A_PROBABILITY), MAX_PROBABILITY);
+    }
+
+    static int getDecayedProbability(const int probability, const HistoricalInfo historicalInfo) {
+        const int elapsedTime = TimeKeeper::peekCurrentTime() - historicalInfo.getTimestamp();
+        if (elapsedTime < 0) {
+            AKLOGE("The elapsed time is negatime value. Timestamp overflow?");
+            return NOT_A_PROBABILITY;
+        }
+        // TODO: Improve this logic.
+        // We don't modify probability depending on the elapsed time.
+        return probability;
+    }
+
+    static int shouldRemoveEntryDuringGC(const HistoricalInfo historicalInfo) {
+        // TODO: Improve this logic.
+        const int elapsedTime = TimeKeeper::peekCurrentTime() - historicalInfo.getTimestamp();
+        return elapsedTime > DURATION_TO_DISCARD_ENTRY_IN_SECONDS;
+    }
+
+    static int getPriorityToPreventFromEviction(const HistoricalInfo historicalInfo) {
+        // TODO: Improve this logic.
+        // More recently input entries get higher priority.
+        return historicalInfo.getTimestamp();
+    }
+
+private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicLanguageModelProbabilityUtils);
+
+    static_assert(MAX_PREV_WORD_COUNT_FOR_N_GRAM <= 3, "Max supported Ngram is Quadgram.");
+
+    static const int ASSUMED_MIN_COUNTS[];
+    static const int ENCODED_BACKOFF_WEIGHTS[];
+    static const int DURATION_TO_DISCARD_ENTRY_IN_SECONDS;
+};
+
+} // namespace latinime
+#endif /* LATINIME_DYNAMIC_LANGUAGE_MODEL_PROBABILITY_UTILS_H */
diff --git a/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.cpp b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.cpp
new file mode 100644
index 000000000..c10e4906b
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.cpp
@@ -0,0 +1,478 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/structure/v4/content/language_model_dict_content.h"
+
+#include <algorithm>
+#include <cstring>
+
+#include "dictionary/structure/v4/content/dynamic_language_model_probability_utils.h"
+#include "dictionary/utils/probability_utils.h"
+#include "utils/ngram_utils.h"
+
+namespace latinime {
+
+const int LanguageModelDictContent::TRIE_MAP_BUFFER_INDEX = 0;
+const int LanguageModelDictContent::GLOBAL_COUNTERS_BUFFER_INDEX = 1;
+
+bool LanguageModelDictContent::save(FILE *const file) const {
+    return mTrieMap.save(file) && mGlobalCounters.save(file);
+}
+
+bool LanguageModelDictContent::runGC(
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const LanguageModelDictContent *const originalContent) {
+    return runGCInner(terminalIdMap, originalContent->mTrieMap.getEntriesInRootLevel(),
+            0 /* nextLevelBitmapEntryIndex */);
+}
+
+const WordAttributes LanguageModelDictContent::getWordAttributes(const WordIdArrayView prevWordIds,
+        const int wordId, const bool mustMatchAllPrevWords,
+        const HeaderPolicy *const headerPolicy) const {
+    int bitmapEntryIndices[MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1];
+    bitmapEntryIndices[0] = mTrieMap.getRootBitmapEntryIndex();
+    int maxPrevWordCount = 0;
+    for (size_t i = 0; i < prevWordIds.size(); ++i) {
+        const int nextBitmapEntryIndex =
+                mTrieMap.get(prevWordIds[i], bitmapEntryIndices[i]).mNextLevelBitmapEntryIndex;
+        if (nextBitmapEntryIndex == TrieMap::INVALID_INDEX) {
+            break;
+        }
+        maxPrevWordCount = i + 1;
+        bitmapEntryIndices[i + 1] = nextBitmapEntryIndex;
+    }
+
+    const ProbabilityEntry unigramProbabilityEntry = getProbabilityEntry(wordId);
+    if (mHasHistoricalInfo && unigramProbabilityEntry.getHistoricalInfo()->getCount() == 0) {
+        // The word should be treated as a invalid word.
+        return WordAttributes();
+    }
+    for (int i = maxPrevWordCount; i >= 0; --i) {
+        if (mustMatchAllPrevWords && prevWordIds.size() > static_cast<size_t>(i)) {
+            break;
+        }
+        const TrieMap::Result result = mTrieMap.get(wordId, bitmapEntryIndices[i]);
+        if (!result.mIsValid) {
+            continue;
+        }
+        const ProbabilityEntry probabilityEntry =
+                ProbabilityEntry::decode(result.mValue, mHasHistoricalInfo);
+        int probability = NOT_A_PROBABILITY;
+        if (mHasHistoricalInfo) {
+            const HistoricalInfo *const historicalInfo = probabilityEntry.getHistoricalInfo();
+            int contextCount = 0;
+            if (i == 0) {
+                // unigram
+                contextCount = mGlobalCounters.getTotalCount();
+            } else {
+                const ProbabilityEntry prevWordProbabilityEntry = getNgramProbabilityEntry(
+                        prevWordIds.skip(1 /* n */).limit(i - 1), prevWordIds[0]);
+                if (!prevWordProbabilityEntry.isValid()) {
+                    continue;
+                }
+                if (prevWordProbabilityEntry.representsBeginningOfSentence()
+                        && historicalInfo->getCount() == 1) {
+                    // BoS ngram requires multiple contextCount.
+                    continue;
+                }
+                contextCount = prevWordProbabilityEntry.getHistoricalInfo()->getCount();
+            }
+            const NgramType ngramType = NgramUtils::getNgramTypeFromWordCount(i + 1);
+            const float rawProbability =
+                    DynamicLanguageModelProbabilityUtils::computeRawProbabilityFromCounts(
+                            historicalInfo->getCount(), contextCount, ngramType);
+            const int encodedRawProbability =
+                    ProbabilityUtils::encodeRawProbability(rawProbability);
+            const int decayedProbability =
+                    DynamicLanguageModelProbabilityUtils::getDecayedProbability(
+                            encodedRawProbability, *historicalInfo);
+            probability = DynamicLanguageModelProbabilityUtils::backoff(
+                    decayedProbability, ngramType);
+        } else {
+            probability = probabilityEntry.getProbability();
+        }
+        // TODO: Some flags in unigramProbabilityEntry should be overwritten by flags in
+        // probabilityEntry.
+        return WordAttributes(probability, unigramProbabilityEntry.isBlacklisted(),
+                unigramProbabilityEntry.isNotAWord(),
+                unigramProbabilityEntry.isPossiblyOffensive());
+    }
+    // Cannot find the word.
+    return WordAttributes();
+}
+
+ProbabilityEntry LanguageModelDictContent::getNgramProbabilityEntry(
+        const WordIdArrayView prevWordIds, const int wordId) const {
+    const int bitmapEntryIndex = getBitmapEntryIndex(prevWordIds);
+    if (bitmapEntryIndex == TrieMap::INVALID_INDEX) {
+        return ProbabilityEntry();
+    }
+    const TrieMap::Result result = mTrieMap.get(wordId, bitmapEntryIndex);
+    if (!result.mIsValid) {
+        // Not found.
+        return ProbabilityEntry();
+    }
+    return ProbabilityEntry::decode(result.mValue, mHasHistoricalInfo);
+}
+
+bool LanguageModelDictContent::setNgramProbabilityEntry(const WordIdArrayView prevWordIds,
+        const int wordId, const ProbabilityEntry *const probabilityEntry) {
+    if (wordId == Ver4DictConstants::NOT_A_TERMINAL_ID) {
+        return false;
+    }
+    const int bitmapEntryIndex = createAndGetBitmapEntryIndex(prevWordIds);
+    if (bitmapEntryIndex == TrieMap::INVALID_INDEX) {
+        return false;
+    }
+    return mTrieMap.put(wordId, probabilityEntry->encode(mHasHistoricalInfo), bitmapEntryIndex);
+}
+
+bool LanguageModelDictContent::removeNgramProbabilityEntry(const WordIdArrayView prevWordIds,
+        const int wordId) {
+    const int bitmapEntryIndex = getBitmapEntryIndex(prevWordIds);
+    if (bitmapEntryIndex == TrieMap::INVALID_INDEX) {
+        // Cannot find bitmap entry for the probability entry. The entry doesn't exist.
+        return false;
+    }
+    return mTrieMap.remove(wordId, bitmapEntryIndex);
+}
+
+LanguageModelDictContent::EntryRange LanguageModelDictContent::getProbabilityEntries(
+        const WordIdArrayView prevWordIds) const {
+    const int bitmapEntryIndex = getBitmapEntryIndex(prevWordIds);
+    return EntryRange(mTrieMap.getEntriesInSpecifiedLevel(bitmapEntryIndex), mHasHistoricalInfo);
+}
+
+std::vector<LanguageModelDictContent::DumppedFullEntryInfo>
+        LanguageModelDictContent::exportAllNgramEntriesRelatedToWord(
+                const HeaderPolicy *const headerPolicy, const int wordId) const {
+    const TrieMap::Result result = mTrieMap.getRoot(wordId);
+    if (!result.mIsValid || result.mNextLevelBitmapEntryIndex == TrieMap::INVALID_INDEX) {
+        // The word doesn't have any related ngram entries.
+        return std::vector<DumppedFullEntryInfo>();
+    }
+    std::vector<int> prevWordIds = { wordId };
+    std::vector<DumppedFullEntryInfo> entries;
+    exportAllNgramEntriesRelatedToWordInner(headerPolicy, result.mNextLevelBitmapEntryIndex,
+            &prevWordIds, &entries);
+    return entries;
+}
+
+void LanguageModelDictContent::exportAllNgramEntriesRelatedToWordInner(
+        const HeaderPolicy *const headerPolicy, const int bitmapEntryIndex,
+        std::vector<int> *const prevWordIds,
+        std::vector<DumppedFullEntryInfo> *const outBummpedFullEntryInfo) const {
+    for (const auto &entry : mTrieMap.getEntriesInSpecifiedLevel(bitmapEntryIndex)) {
+        const int wordId = entry.key();
+        const ProbabilityEntry probabilityEntry =
+                ProbabilityEntry::decode(entry.value(), mHasHistoricalInfo);
+        if (probabilityEntry.isValid()) {
+            const WordAttributes wordAttributes = getWordAttributes(
+                    WordIdArrayView(*prevWordIds), wordId, true /* mustMatchAllPrevWords */,
+                    headerPolicy);
+            outBummpedFullEntryInfo->emplace_back(*prevWordIds, wordId,
+                    wordAttributes, probabilityEntry);
+        }
+        if (entry.hasNextLevelMap()) {
+            prevWordIds->push_back(wordId);
+            exportAllNgramEntriesRelatedToWordInner(headerPolicy,
+                    entry.getNextLevelBitmapEntryIndex(), prevWordIds, outBummpedFullEntryInfo);
+            prevWordIds->pop_back();
+        }
+    }
+}
+
+bool LanguageModelDictContent::truncateEntries(const EntryCounts &currentEntryCounts,
+        const EntryCounts &maxEntryCounts, const HeaderPolicy *const headerPolicy,
+        MutableEntryCounters *const outEntryCounters) {
+    for (int prevWordCount = 0; prevWordCount <= MAX_PREV_WORD_COUNT_FOR_N_GRAM; ++prevWordCount) {
+        const int totalWordCount = prevWordCount + 1;
+        const NgramType ngramType = NgramUtils::getNgramTypeFromWordCount(totalWordCount);
+        if (currentEntryCounts.getNgramCount(ngramType)
+                <= maxEntryCounts.getNgramCount(ngramType)) {
+            outEntryCounters->setNgramCount(ngramType,
+                    currentEntryCounts.getNgramCount(ngramType));
+            continue;
+        }
+        int entryCount = 0;
+        if (!turncateEntriesInSpecifiedLevel(headerPolicy,
+                maxEntryCounts.getNgramCount(ngramType), prevWordCount, &entryCount)) {
+            return false;
+        }
+        outEntryCounters->setNgramCount(ngramType, entryCount);
+    }
+    return true;
+}
+
+bool LanguageModelDictContent::updateAllEntriesOnInputWord(const WordIdArrayView prevWordIds,
+        const int wordId, const bool isValid, const HistoricalInfo historicalInfo,
+        const HeaderPolicy *const headerPolicy, MutableEntryCounters *const entryCountersToUpdate) {
+    if (!mHasHistoricalInfo) {
+        AKLOGE("updateAllEntriesOnInputWord is called for dictionary without historical info.");
+        return false;
+    }
+    const ProbabilityEntry originalUnigramProbabilityEntry = getProbabilityEntry(wordId);
+    const ProbabilityEntry updatedUnigramProbabilityEntry = createUpdatedEntryFrom(
+            originalUnigramProbabilityEntry, isValid, historicalInfo, headerPolicy);
+    if (!setProbabilityEntry(wordId, &updatedUnigramProbabilityEntry)) {
+        return false;
+    }
+    mGlobalCounters.incrementTotalCount();
+    mGlobalCounters.updateMaxValueOfCounters(
+            updatedUnigramProbabilityEntry.getHistoricalInfo()->getCount());
+    for (size_t i = 0; i < prevWordIds.size(); ++i) {
+        if (prevWordIds[i] == NOT_A_WORD_ID) {
+            break;
+        }
+        // TODO: Optimize this code.
+        const WordIdArrayView limitedPrevWordIds = prevWordIds.limit(i + 1);
+        const ProbabilityEntry originalNgramProbabilityEntry = getNgramProbabilityEntry(
+                limitedPrevWordIds, wordId);
+        const ProbabilityEntry updatedNgramProbabilityEntry = createUpdatedEntryFrom(
+                originalNgramProbabilityEntry, isValid, historicalInfo, headerPolicy);
+        if (!setNgramProbabilityEntry(limitedPrevWordIds, wordId, &updatedNgramProbabilityEntry)) {
+            return false;
+        }
+        mGlobalCounters.updateMaxValueOfCounters(
+                updatedNgramProbabilityEntry.getHistoricalInfo()->getCount());
+        if (!originalNgramProbabilityEntry.isValid()) {
+            // (i + 2) words are used in total because the prevWords consists of (i + 1) words when
+            // looking at its i-th element.
+            entryCountersToUpdate->incrementNgramCount(
+                    NgramUtils::getNgramTypeFromWordCount(i + 2));
+        }
+    }
+    return true;
+}
+
+const ProbabilityEntry LanguageModelDictContent::createUpdatedEntryFrom(
+        const ProbabilityEntry &originalProbabilityEntry, const bool isValid,
+        const HistoricalInfo historicalInfo, const HeaderPolicy *const headerPolicy) const {
+    const HistoricalInfo updatedHistoricalInfo = HistoricalInfo(historicalInfo.getTimestamp(),
+            0 /* level */, originalProbabilityEntry.getHistoricalInfo()->getCount()
+                    + historicalInfo.getCount());
+    if (originalProbabilityEntry.isValid()) {
+        return ProbabilityEntry(originalProbabilityEntry.getFlags(), &updatedHistoricalInfo);
+    } else {
+        return ProbabilityEntry(0 /* flags */, &updatedHistoricalInfo);
+    }
+}
+
+bool LanguageModelDictContent::runGCInner(
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const TrieMap::TrieMapRange trieMapRange, const int nextLevelBitmapEntryIndex) {
+    for (auto &entry : trieMapRange) {
+        const auto it = terminalIdMap->find(entry.key());
+        if (it == terminalIdMap->end() || it->second == Ver4DictConstants::NOT_A_TERMINAL_ID) {
+            // The word has been removed.
+            continue;
+        }
+        if (!mTrieMap.put(it->second, entry.value(), nextLevelBitmapEntryIndex)) {
+            return false;
+        }
+        if (entry.hasNextLevelMap()) {
+            if (!runGCInner(terminalIdMap, entry.getEntriesInNextLevel(),
+                    mTrieMap.getNextLevelBitmapEntryIndex(it->second, nextLevelBitmapEntryIndex))) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+int LanguageModelDictContent::createAndGetBitmapEntryIndex(const WordIdArrayView prevWordIds) {
+    int lastBitmapEntryIndex = mTrieMap.getRootBitmapEntryIndex();
+    for (const int wordId : prevWordIds) {
+        const TrieMap::Result result = mTrieMap.get(wordId, lastBitmapEntryIndex);
+        if (result.mIsValid && result.mNextLevelBitmapEntryIndex != TrieMap::INVALID_INDEX) {
+            lastBitmapEntryIndex = result.mNextLevelBitmapEntryIndex;
+            continue;
+        }
+        if (!result.mIsValid) {
+            if (!mTrieMap.put(wordId, ProbabilityEntry().encode(mHasHistoricalInfo),
+                    lastBitmapEntryIndex)) {
+                AKLOGE("Failed to update trie map. wordId: %d, lastBitmapEntryIndex %d", wordId,
+                        lastBitmapEntryIndex);
+                return TrieMap::INVALID_INDEX;
+            }
+        }
+        lastBitmapEntryIndex = mTrieMap.getNextLevelBitmapEntryIndex(wordId,
+                lastBitmapEntryIndex);
+    }
+    return lastBitmapEntryIndex;
+}
+
+int LanguageModelDictContent::getBitmapEntryIndex(const WordIdArrayView prevWordIds) const {
+    int bitmapEntryIndex = mTrieMap.getRootBitmapEntryIndex();
+    for (const int wordId : prevWordIds) {
+        const TrieMap::Result result = mTrieMap.get(wordId, bitmapEntryIndex);
+        if (!result.mIsValid) {
+            return TrieMap::INVALID_INDEX;
+        }
+        bitmapEntryIndex = result.mNextLevelBitmapEntryIndex;
+    }
+    return bitmapEntryIndex;
+}
+
+bool LanguageModelDictContent::updateAllProbabilityEntriesForGCInner(const int bitmapEntryIndex,
+        const int prevWordCount, const HeaderPolicy *const headerPolicy,
+        const bool needsToHalveCounters, MutableEntryCounters *const outEntryCounters) {
+    for (const auto &entry : mTrieMap.getEntriesInSpecifiedLevel(bitmapEntryIndex)) {
+        if (prevWordCount > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
+            AKLOGE("Invalid prevWordCount. prevWordCount: %d, MAX_PREV_WORD_COUNT_FOR_N_GRAM: %d.",
+                    prevWordCount, MAX_PREV_WORD_COUNT_FOR_N_GRAM);
+            return false;
+        }
+        const ProbabilityEntry probabilityEntry =
+                ProbabilityEntry::decode(entry.value(), mHasHistoricalInfo);
+        if (prevWordCount > 0 && probabilityEntry.isValid()
+                && !mTrieMap.getRoot(entry.key()).mIsValid) {
+            // The entry is related to a word that has been removed. Remove the entry.
+            if (!mTrieMap.remove(entry.key(), bitmapEntryIndex)) {
+                return false;
+            }
+            continue;
+        }
+        if (mHasHistoricalInfo && probabilityEntry.isValid()) {
+            const HistoricalInfo *originalHistoricalInfo = probabilityEntry.getHistoricalInfo();
+            if (DynamicLanguageModelProbabilityUtils::shouldRemoveEntryDuringGC(
+                    *originalHistoricalInfo)) {
+                // Remove the entry.
+                if (!mTrieMap.remove(entry.key(), bitmapEntryIndex)) {
+                    return false;
+                }
+                continue;
+            }
+            if (needsToHalveCounters) {
+                const int updatedCount = originalHistoricalInfo->getCount() / 2;
+                if (updatedCount == 0) {
+                    // Remove the entry.
+                    if (!mTrieMap.remove(entry.key(), bitmapEntryIndex)) {
+                        return false;
+                    }
+                    continue;
+                }
+                const HistoricalInfo historicalInfoToSave(originalHistoricalInfo->getTimestamp(),
+                        originalHistoricalInfo->getLevel(), updatedCount);
+                const ProbabilityEntry updatedEntry(probabilityEntry.getFlags(),
+                        &historicalInfoToSave);
+                if (!mTrieMap.put(entry.key(), updatedEntry.encode(mHasHistoricalInfo),
+                        bitmapEntryIndex)) {
+                    return false;
+                }
+            }
+        }
+        outEntryCounters->incrementNgramCount(
+                NgramUtils::getNgramTypeFromWordCount(prevWordCount + 1));
+        if (!entry.hasNextLevelMap()) {
+            continue;
+        }
+        if (!updateAllProbabilityEntriesForGCInner(entry.getNextLevelBitmapEntryIndex(),
+                prevWordCount + 1, headerPolicy, needsToHalveCounters, outEntryCounters)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool LanguageModelDictContent::turncateEntriesInSpecifiedLevel(
+        const HeaderPolicy *const headerPolicy, const int maxEntryCount, const int targetLevel,
+        int *const outEntryCount) {
+    std::vector<int> prevWordIds;
+    std::vector<EntryInfoToTurncate> entryInfoVector;
+    if (!getEntryInfo(headerPolicy, targetLevel, mTrieMap.getRootBitmapEntryIndex(),
+            &prevWordIds, &entryInfoVector)) {
+        return false;
+    }
+    if (static_cast<int>(entryInfoVector.size()) <= maxEntryCount) {
+        *outEntryCount = static_cast<int>(entryInfoVector.size());
+        return true;
+    }
+    *outEntryCount = maxEntryCount;
+    const int entryCountToRemove = static_cast<int>(entryInfoVector.size()) - maxEntryCount;
+    std::partial_sort(entryInfoVector.begin(), entryInfoVector.begin() + entryCountToRemove,
+            entryInfoVector.end(),
+            EntryInfoToTurncate::Comparator());
+    for (int i = 0; i < entryCountToRemove; ++i) {
+        const EntryInfoToTurncate &entryInfo = entryInfoVector[i];
+        if (!removeNgramProbabilityEntry(
+                WordIdArrayView(entryInfo.mPrevWordIds, entryInfo.mPrevWordCount),
+                entryInfo.mKey)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool LanguageModelDictContent::getEntryInfo(const HeaderPolicy *const headerPolicy,
+        const int targetLevel, const int bitmapEntryIndex,  std::vector<int> *const prevWordIds,
+        std::vector<EntryInfoToTurncate> *const outEntryInfo) const {
+    const int prevWordCount = prevWordIds->size();
+    for (const auto &entry : mTrieMap.getEntriesInSpecifiedLevel(bitmapEntryIndex)) {
+        if (prevWordCount < targetLevel) {
+            if (!entry.hasNextLevelMap()) {
+                continue;
+            }
+            prevWordIds->push_back(entry.key());
+            if (!getEntryInfo(headerPolicy, targetLevel, entry.getNextLevelBitmapEntryIndex(),
+                    prevWordIds, outEntryInfo)) {
+                return false;
+            }
+            prevWordIds->pop_back();
+            continue;
+        }
+        const ProbabilityEntry probabilityEntry =
+                ProbabilityEntry::decode(entry.value(), mHasHistoricalInfo);
+        const int priority = mHasHistoricalInfo
+                ? DynamicLanguageModelProbabilityUtils::getPriorityToPreventFromEviction(
+                        *probabilityEntry.getHistoricalInfo())
+                : probabilityEntry.getProbability();
+        outEntryInfo->emplace_back(priority, probabilityEntry.getHistoricalInfo()->getCount(),
+                entry.key(), targetLevel, prevWordIds->data());
+    }
+    return true;
+}
+
+bool LanguageModelDictContent::EntryInfoToTurncate::Comparator::operator()(
+        const EntryInfoToTurncate &left, const EntryInfoToTurncate &right) const {
+    if (left.mPriority != right.mPriority) {
+        return left.mPriority < right.mPriority;
+    }
+    if (left.mCount != right.mCount) {
+        return left.mCount < right.mCount;
+    }
+    if (left.mKey != right.mKey) {
+        return left.mKey < right.mKey;
+    }
+    if (left.mPrevWordCount != right.mPrevWordCount) {
+        return left.mPrevWordCount > right.mPrevWordCount;
+    }
+    for (int i = 0; i < left.mPrevWordCount; ++i) {
+        if (left.mPrevWordIds[i] != right.mPrevWordIds[i]) {
+            return left.mPrevWordIds[i] < right.mPrevWordIds[i];
+        }
+    }
+    // left and rigth represent the same entry.
+    return false;
+}
+
+LanguageModelDictContent::EntryInfoToTurncate::EntryInfoToTurncate(const int priority,
+        const int count, const int key, const int prevWordCount, const int *const prevWordIds)
+        : mPriority(priority), mCount(count), mKey(key), mPrevWordCount(prevWordCount) {
+    memmove(mPrevWordIds, prevWordIds, mPrevWordCount * sizeof(mPrevWordIds[0]));
+}
+
+} // namespace latinime
diff --git a/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.h b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.h
new file mode 100644
index 000000000..db8c6e12b
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content.h
@@ -0,0 +1,258 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H
+#define LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H
+
+#include <cstdio>
+#include <vector>
+
+#include "defines.h"
+#include "dictionary/property/word_attributes.h"
+#include "dictionary/structure/v4/content/language_model_dict_content_global_counters.h"
+#include "dictionary/structure/v4/content/probability_entry.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/utils/entry_counters.h"
+#include "dictionary/utils/trie_map.h"
+#include "utils/byte_array_view.h"
+#include "utils/int_array_view.h"
+
+namespace latinime {
+
+class HeaderPolicy;
+
+/**
+ * Class representing language model.
+ *
+ * This class provides methods to get and store unigram/n-gram probability information and flags.
+ */
+class LanguageModelDictContent {
+ public:
+    // Pair of word id and probability entry used for iteration.
+    class WordIdAndProbabilityEntry {
+     public:
+        WordIdAndProbabilityEntry(const int wordId, const ProbabilityEntry &probabilityEntry)
+                : mWordId(wordId), mProbabilityEntry(probabilityEntry) {}
+
+        int getWordId() const { return mWordId; }
+        const ProbabilityEntry getProbabilityEntry() const { return mProbabilityEntry; }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(WordIdAndProbabilityEntry);
+        DISALLOW_ASSIGNMENT_OPERATOR(WordIdAndProbabilityEntry);
+
+        const int mWordId;
+        const ProbabilityEntry mProbabilityEntry;
+    };
+
+    // Iterator.
+    class EntryIterator {
+     public:
+        EntryIterator(const TrieMap::TrieMapIterator &trieMapIterator,
+                const bool hasHistoricalInfo)
+                : mTrieMapIterator(trieMapIterator), mHasHistoricalInfo(hasHistoricalInfo) {}
+
+        const WordIdAndProbabilityEntry operator*() const {
+            const TrieMap::TrieMapIterator::IterationResult &result = *mTrieMapIterator;
+            return WordIdAndProbabilityEntry(
+                    result.key(), ProbabilityEntry::decode(result.value(), mHasHistoricalInfo));
+        }
+
+        bool operator!=(const EntryIterator &other) const {
+            return mTrieMapIterator != other.mTrieMapIterator;
+        }
+
+        const EntryIterator &operator++() {
+            ++mTrieMapIterator;
+            return *this;
+        }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(EntryIterator);
+        DISALLOW_ASSIGNMENT_OPERATOR(EntryIterator);
+
+        TrieMap::TrieMapIterator mTrieMapIterator;
+        const bool mHasHistoricalInfo;
+    };
+
+    // Class represents range to use range base for loops.
+    class EntryRange {
+     public:
+        EntryRange(const TrieMap::TrieMapRange trieMapRange, const bool hasHistoricalInfo)
+                : mTrieMapRange(trieMapRange), mHasHistoricalInfo(hasHistoricalInfo) {}
+
+        EntryIterator begin() const {
+            return EntryIterator(mTrieMapRange.begin(), mHasHistoricalInfo);
+        }
+
+        EntryIterator end() const {
+            return EntryIterator(mTrieMapRange.end(), mHasHistoricalInfo);
+        }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(EntryRange);
+        DISALLOW_ASSIGNMENT_OPERATOR(EntryRange);
+
+        const TrieMap::TrieMapRange mTrieMapRange;
+        const bool mHasHistoricalInfo;
+    };
+
+    class DumppedFullEntryInfo {
+     public:
+        DumppedFullEntryInfo(std::vector<int> &prevWordIds, const int targetWordId,
+                const WordAttributes &wordAttributes, const ProbabilityEntry &probabilityEntry)
+                : mPrevWordIds(prevWordIds), mTargetWordId(targetWordId),
+                  mWordAttributes(wordAttributes), mProbabilityEntry(probabilityEntry) {}
+
+        const WordIdArrayView getPrevWordIds() const { return WordIdArrayView(mPrevWordIds); }
+        int getTargetWordId() const { return mTargetWordId; }
+        const WordAttributes &getWordAttributes() const { return mWordAttributes; }
+        const ProbabilityEntry &getProbabilityEntry() const { return mProbabilityEntry; }
+
+     private:
+        DISALLOW_ASSIGNMENT_OPERATOR(DumppedFullEntryInfo);
+
+        const std::vector<int> mPrevWordIds;
+        const int mTargetWordId;
+        const WordAttributes mWordAttributes;
+        const ProbabilityEntry mProbabilityEntry;
+    };
+
+    LanguageModelDictContent(const ReadWriteByteArrayView *const buffers,
+            const bool hasHistoricalInfo)
+            : mTrieMap(buffers[TRIE_MAP_BUFFER_INDEX]),
+              mGlobalCounters(buffers[GLOBAL_COUNTERS_BUFFER_INDEX]),
+              mHasHistoricalInfo(hasHistoricalInfo) {}
+
+    explicit LanguageModelDictContent(const bool hasHistoricalInfo)
+            : mTrieMap(), mGlobalCounters(), mHasHistoricalInfo(hasHistoricalInfo) {}
+
+    bool isNearSizeLimit() const {
+        return mTrieMap.isNearSizeLimit() || mGlobalCounters.needsToHalveCounters();
+    }
+
+    bool save(FILE *const file) const;
+
+    bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+            const LanguageModelDictContent *const originalContent);
+
+    const WordAttributes getWordAttributes(const WordIdArrayView prevWordIds, const int wordId,
+            const bool mustMatchAllPrevWords, const HeaderPolicy *const headerPolicy) const;
+
+    ProbabilityEntry getProbabilityEntry(const int wordId) const {
+        return getNgramProbabilityEntry(WordIdArrayView(), wordId);
+    }
+
+    bool setProbabilityEntry(const int wordId, const ProbabilityEntry *const probabilityEntry) {
+        mGlobalCounters.addToTotalCount(probabilityEntry->getHistoricalInfo()->getCount());
+        return setNgramProbabilityEntry(WordIdArrayView(), wordId, probabilityEntry);
+    }
+
+    bool removeProbabilityEntry(const int wordId) {
+        return removeNgramProbabilityEntry(WordIdArrayView(), wordId);
+    }
+
+    ProbabilityEntry getNgramProbabilityEntry(const WordIdArrayView prevWordIds,
+            const int wordId) const;
+
+    bool setNgramProbabilityEntry(const WordIdArrayView prevWordIds, const int wordId,
+            const ProbabilityEntry *const probabilityEntry);
+
+    bool removeNgramProbabilityEntry(const WordIdArrayView prevWordIds, const int wordId);
+
+    EntryRange getProbabilityEntries(const WordIdArrayView prevWordIds) const;
+
+    std::vector<DumppedFullEntryInfo> exportAllNgramEntriesRelatedToWord(
+            const HeaderPolicy *const headerPolicy, const int wordId) const;
+
+    bool updateAllProbabilityEntriesForGC(const HeaderPolicy *const headerPolicy,
+            MutableEntryCounters *const outEntryCounters) {
+        if (!updateAllProbabilityEntriesForGCInner(mTrieMap.getRootBitmapEntryIndex(),
+                0 /* prevWordCount */, headerPolicy, mGlobalCounters.needsToHalveCounters(),
+                outEntryCounters)) {
+            return false;
+        }
+        if (mGlobalCounters.needsToHalveCounters()) {
+            mGlobalCounters.halveCounters();
+        }
+        return true;
+    }
+
+    // entryCounts should be created by updateAllProbabilityEntries.
+    bool truncateEntries(const EntryCounts &currentEntryCounts, const EntryCounts &maxEntryCounts,
+            const HeaderPolicy *const headerPolicy, MutableEntryCounters *const outEntryCounters);
+
+    bool updateAllEntriesOnInputWord(const WordIdArrayView prevWordIds, const int wordId,
+            const bool isValid, const HistoricalInfo historicalInfo,
+            const HeaderPolicy *const headerPolicy,
+            MutableEntryCounters *const entryCountersToUpdate);
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(LanguageModelDictContent);
+
+    class EntryInfoToTurncate {
+     public:
+        class Comparator {
+         public:
+            bool operator()(const EntryInfoToTurncate &left,
+                    const EntryInfoToTurncate &right) const;
+         private:
+            DISALLOW_ASSIGNMENT_OPERATOR(Comparator);
+        };
+
+        EntryInfoToTurncate(const int priority, const int count, const int key,
+                const int prevWordCount, const int *const prevWordIds);
+
+        int mPriority;
+        // TODO: Remove.
+        int mCount;
+        int mKey;
+        int mPrevWordCount;
+        int mPrevWordIds[MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1];
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(EntryInfoToTurncate);
+    };
+
+    static const int TRIE_MAP_BUFFER_INDEX;
+    static const int GLOBAL_COUNTERS_BUFFER_INDEX;
+
+    TrieMap mTrieMap;
+    LanguageModelDictContentGlobalCounters mGlobalCounters;
+    const bool mHasHistoricalInfo;
+
+    bool runGCInner(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+            const TrieMap::TrieMapRange trieMapRange, const int nextLevelBitmapEntryIndex);
+    int createAndGetBitmapEntryIndex(const WordIdArrayView prevWordIds);
+    int getBitmapEntryIndex(const WordIdArrayView prevWordIds) const;
+    bool updateAllProbabilityEntriesForGCInner(const int bitmapEntryIndex, const int prevWordCount,
+            const HeaderPolicy *const headerPolicy, const bool needsToHalveCounters,
+            MutableEntryCounters *const outEntryCounters);
+    bool turncateEntriesInSpecifiedLevel(const HeaderPolicy *const headerPolicy,
+            const int maxEntryCount, const int targetLevel, int *const outEntryCount);
+    bool getEntryInfo(const HeaderPolicy *const headerPolicy, const int targetLevel,
+            const int bitmapEntryIndex, std::vector<int> *const prevWordIds,
+            std::vector<EntryInfoToTurncate> *const outEntryInfo) const;
+    const ProbabilityEntry createUpdatedEntryFrom(const ProbabilityEntry &originalProbabilityEntry,
+            const bool isValid, const HistoricalInfo historicalInfo,
+            const HeaderPolicy *const headerPolicy) const;
+    void exportAllNgramEntriesRelatedToWordInner(const HeaderPolicy *const headerPolicy,
+            const int bitmapEntryIndex, std::vector<int> *const prevWordIds,
+            std::vector<DumppedFullEntryInfo> *const outBummpedFullEntryInfo) const;
+};
+} // namespace latinime
+#endif /* LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H */
diff --git a/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.cpp b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.cpp
new file mode 100644
index 000000000..89cf0e306
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.cpp
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/structure/v4/content/language_model_dict_content_global_counters.h"
+
+#include <climits>
+
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+
+namespace latinime {
+
+const int LanguageModelDictContentGlobalCounters::COUNTER_VALUE_NEAR_LIMIT_THRESHOLD =
+        (1 << (Ver4DictConstants::WORD_COUNT_FIELD_SIZE * CHAR_BIT)) - 64;
+const int LanguageModelDictContentGlobalCounters::TOTAL_COUNT_VALUE_NEAR_LIMIT_THRESHOLD = 1 << 30;
+const int LanguageModelDictContentGlobalCounters::COUNTER_SIZE_IN_BYTES = 4;
+const int LanguageModelDictContentGlobalCounters::TOTAL_COUNT_INDEX = 0;
+const int LanguageModelDictContentGlobalCounters::MAX_VALUE_OF_COUNTERS_INDEX = 1;
+
+} // namespace latinime
diff --git a/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.h b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.h
new file mode 100644
index 000000000..3f87c0ea0
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/content/language_model_dict_content_global_counters.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_LANGUAGE_MODEL_DICT_CONTENT_GLOBAL_COUNTERS_H
+#define LATINIME_LANGUAGE_MODEL_DICT_CONTENT_GLOBAL_COUNTERS_H
+
+#include <cstdio>
+
+#include "defines.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "utils/byte_array_view.h"
+
+namespace latinime {
+
+class LanguageModelDictContentGlobalCounters {
+ public:
+    explicit LanguageModelDictContentGlobalCounters(const ReadWriteByteArrayView buffer)
+            : mBuffer(buffer, 0 /* maxAdditionalBufferSize */),
+              mTotalCount(readValue(mBuffer, TOTAL_COUNT_INDEX)),
+              mMaxValueOfCounters(readValue(mBuffer, MAX_VALUE_OF_COUNTERS_INDEX)) {}
+
+    LanguageModelDictContentGlobalCounters()
+            : mBuffer(0 /* maxAdditionalBufferSize */), mTotalCount(0), mMaxValueOfCounters(0) {}
+
+    bool needsToHalveCounters() const {
+        return mMaxValueOfCounters >= COUNTER_VALUE_NEAR_LIMIT_THRESHOLD
+                || mTotalCount >= TOTAL_COUNT_VALUE_NEAR_LIMIT_THRESHOLD;
+    }
+
+    int getTotalCount() const {
+        return mTotalCount;
+    }
+
+    bool save(FILE *const file) const {
+        BufferWithExtendableBuffer bufferToWrite(
+                BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+        if (!bufferToWrite.writeUint(mTotalCount, COUNTER_SIZE_IN_BYTES,
+                TOTAL_COUNT_INDEX * COUNTER_SIZE_IN_BYTES)) {
+            return false;
+        }
+        if (!bufferToWrite.writeUint(mMaxValueOfCounters, COUNTER_SIZE_IN_BYTES,
+                MAX_VALUE_OF_COUNTERS_INDEX * COUNTER_SIZE_IN_BYTES)) {
+            return false;
+        }
+        return DictFileWritingUtils::writeBufferToFileTail(file, &bufferToWrite);
+    }
+
+    void incrementTotalCount() {
+        mTotalCount += 1;
+    }
+
+    void addToTotalCount(const int count) {
+        mTotalCount += count;
+    }
+
+    void updateMaxValueOfCounters(const int count) {
+        mMaxValueOfCounters = std::max(count, mMaxValueOfCounters);
+    }
+
+    void halveCounters() {
+        mMaxValueOfCounters /= 2;
+        mTotalCount /= 2;
+    }
+
+private:
+    DISALLOW_COPY_AND_ASSIGN(LanguageModelDictContentGlobalCounters);
+
+    const static int COUNTER_VALUE_NEAR_LIMIT_THRESHOLD;
+    const static int TOTAL_COUNT_VALUE_NEAR_LIMIT_THRESHOLD;
+    const static int COUNTER_SIZE_IN_BYTES;
+    const static int TOTAL_COUNT_INDEX;
+    const static int MAX_VALUE_OF_COUNTERS_INDEX;
+
+    BufferWithExtendableBuffer mBuffer;
+    int mTotalCount;
+    int mMaxValueOfCounters;
+
+    static int readValue(const BufferWithExtendableBuffer &buffer, const int index) {
+        const int pos = COUNTER_SIZE_IN_BYTES * index;
+        if (pos + COUNTER_SIZE_IN_BYTES > buffer.getTailPosition()) {
+            return 0;
+        }
+        return buffer.readUint(COUNTER_SIZE_IN_BYTES, pos);
+    }
+};
+} // namespace latinime
+#endif /* LATINIME_LANGUAGE_MODEL_DICT_CONTENT_GLOBAL_COUNTERS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h b/native/jni/src/dictionary/structure/v4/content/probability_entry.h
index feff6b57f..473354b90 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h
+++ b/native/jni/src/dictionary/structure/v4/content/probability_entry.h
@@ -21,8 +21,10 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/property/ngram_property.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
 
 namespace latinime {
 
@@ -34,31 +36,40 @@ class ProbabilityEntry {
 
     // Dummy entry
     ProbabilityEntry()
-            : mFlags(0), mProbability(NOT_A_PROBABILITY), mHistoricalInfo() {}
+            : mFlags(Ver4DictConstants::FLAG_NOT_A_VALID_ENTRY), mProbability(NOT_A_PROBABILITY),
+              mHistoricalInfo() {}
 
     // Entry without historical information
     ProbabilityEntry(const int flags, const int probability)
             : mFlags(flags), mProbability(probability), mHistoricalInfo() {}
 
     // Entry with historical information.
-    ProbabilityEntry(const int flags, const int probability,
-            const HistoricalInfo *const historicalInfo)
-            : mFlags(flags), mProbability(probability), mHistoricalInfo(*historicalInfo) {}
-
-    const ProbabilityEntry createEntryWithUpdatedProbability(const int probability) const {
-        return ProbabilityEntry(mFlags, probability, &mHistoricalInfo);
-    }
-
-    const ProbabilityEntry createEntryWithUpdatedHistoricalInfo(
-            const HistoricalInfo *const historicalInfo) const {
-        return ProbabilityEntry(mFlags, mProbability, historicalInfo);
+    ProbabilityEntry(const int flags, const HistoricalInfo *const historicalInfo)
+            : mFlags(flags), mProbability(NOT_A_PROBABILITY), mHistoricalInfo(*historicalInfo) {}
+
+    // Create from unigram property.
+    ProbabilityEntry(const UnigramProperty *const unigramProperty)
+            : mFlags(createFlags(unigramProperty->representsBeginningOfSentence(),
+                    unigramProperty->isNotAWord(), unigramProperty->isBlacklisted(),
+                    unigramProperty->isPossiblyOffensive())),
+              mProbability(unigramProperty->getProbability()),
+              mHistoricalInfo(unigramProperty->getHistoricalInfo()) {}
+
+    // Create from ngram property.
+    // TODO: Set flags.
+    ProbabilityEntry(const NgramProperty *const ngramProperty)
+            : mFlags(0), mProbability(ngramProperty->getProbability()),
+              mHistoricalInfo(ngramProperty->getHistoricalInfo()) {}
+
+    bool isValid() const {
+        return (mFlags & Ver4DictConstants::FLAG_NOT_A_VALID_ENTRY) == 0;
     }
 
     bool hasHistoricalInfo() const {
         return mHistoricalInfo.isValid();
     }
 
-    int getFlags() const {
+    uint8_t getFlags() const {
         return mFlags;
     }
 
@@ -70,18 +81,34 @@ class ProbabilityEntry {
         return &mHistoricalInfo;
     }
 
+    bool representsBeginningOfSentence() const {
+        return (mFlags & Ver4DictConstants::FLAG_REPRESENTS_BEGINNING_OF_SENTENCE) != 0;
+    }
+
+    bool isNotAWord() const {
+        return (mFlags & Ver4DictConstants::FLAG_NOT_A_WORD) != 0;
+    }
+
+    bool isBlacklisted() const {
+        return (mFlags & Ver4DictConstants::FLAG_BLACKLISTED) != 0;
+    }
+
+    bool isPossiblyOffensive() const {
+        return (mFlags & Ver4DictConstants::FLAG_POSSIBLY_OFFENSIVE) != 0;
+    }
+
     uint64_t encode(const bool hasHistoricalInfo) const {
-        uint64_t encodedEntry = static_cast<uint64_t>(mFlags);
+        uint64_t encodedEntry = static_cast<uint8_t>(mFlags);
         if (hasHistoricalInfo) {
             encodedEntry = (encodedEntry << (Ver4DictConstants::TIME_STAMP_FIELD_SIZE * CHAR_BIT))
-                    ^ static_cast<uint64_t>(mHistoricalInfo.getTimeStamp());
+                    | static_cast<uint32_t>(mHistoricalInfo.getTimestamp());
             encodedEntry = (encodedEntry << (Ver4DictConstants::WORD_LEVEL_FIELD_SIZE * CHAR_BIT))
-                    ^ static_cast<uint64_t>(mHistoricalInfo.getLevel());
+                    | static_cast<uint8_t>(mHistoricalInfo.getLevel());
             encodedEntry = (encodedEntry << (Ver4DictConstants::WORD_COUNT_FIELD_SIZE * CHAR_BIT))
-                    ^ static_cast<uint64_t>(mHistoricalInfo.getCount());
+                    | static_cast<uint16_t>(mHistoricalInfo.getCount());
         } else {
             encodedEntry = (encodedEntry << (Ver4DictConstants::PROBABILITY_SIZE * CHAR_BIT))
-                    ^ static_cast<uint64_t>(mProbability);
+                    | static_cast<uint8_t>(mProbability);
         }
         return encodedEntry;
     }
@@ -89,7 +116,7 @@ class ProbabilityEntry {
     static ProbabilityEntry decode(const uint64_t encodedEntry, const bool hasHistoricalInfo) {
         if (hasHistoricalInfo) {
             const int flags = readFromEncodedEntry(encodedEntry,
-                    Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE,
+                    Ver4DictConstants::FLAGS_IN_LANGUAGE_MODEL_SIZE,
                     Ver4DictConstants::TIME_STAMP_FIELD_SIZE
                             + Ver4DictConstants::WORD_LEVEL_FIELD_SIZE
                             + Ver4DictConstants::WORD_COUNT_FIELD_SIZE);
@@ -103,10 +130,10 @@ class ProbabilityEntry {
             const int count = readFromEncodedEntry(encodedEntry,
                     Ver4DictConstants::WORD_COUNT_FIELD_SIZE, 0 /* pos */);
             const HistoricalInfo historicalInfo(timestamp, level, count);
-            return ProbabilityEntry(flags, NOT_A_PROBABILITY, &historicalInfo);
+            return ProbabilityEntry(flags, &historicalInfo);
         } else {
             const int flags = readFromEncodedEntry(encodedEntry,
-                    Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE,
+                    Ver4DictConstants::FLAGS_IN_LANGUAGE_MODEL_SIZE,
                     Ver4DictConstants::PROBABILITY_SIZE);
             const int probability = readFromEncodedEntry(encodedEntry,
                     Ver4DictConstants::PROBABILITY_SIZE, 0 /* pos */);
@@ -118,7 +145,7 @@ class ProbabilityEntry {
     // Copy constructor is public to use this class as a type of return value.
     DISALLOW_ASSIGNMENT_OPERATOR(ProbabilityEntry);
 
-    const int mFlags;
+    const uint8_t mFlags;
     const int mProbability;
     const HistoricalInfo mHistoricalInfo;
 
@@ -126,6 +153,24 @@ class ProbabilityEntry {
         return static_cast<int>(
                 (encodedEntry >> (pos * CHAR_BIT)) & ((1ull << (size * CHAR_BIT)) - 1));
     }
+
+    static uint8_t createFlags(const bool representsBeginningOfSentence,
+            const bool isNotAWord, const bool isBlacklisted, const bool isPossiblyOffensive) {
+        uint8_t flags = 0;
+        if (representsBeginningOfSentence) {
+            flags |= Ver4DictConstants::FLAG_REPRESENTS_BEGINNING_OF_SENTENCE;
+        }
+        if (isNotAWord) {
+            flags |= Ver4DictConstants::FLAG_NOT_A_WORD;
+        }
+        if (isBlacklisted) {
+            flags |= Ver4DictConstants::FLAG_BLACKLISTED;
+        }
+        if (isPossiblyOffensive) {
+            flags |= Ver4DictConstants::FLAG_POSSIBLY_OFFENSIVE;
+        }
+        return flags;
+    }
 };
 } // namespace latinime
 #endif /* LATINIME_PROBABILITY_ENTRY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.cpp b/native/jni/src/dictionary/structure/v4/content/shortcut_dict_content.cpp
index 41d9c544c..e3b419449 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/v4/content/shortcut_dict_content.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h"
+#include "dictionary/structure/v4/content/shortcut_dict_content.h"
 
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h b/native/jni/src/dictionary/structure/v4/content/shortcut_dict_content.h
index 7b12aff16..27de4e79e 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h
+++ b/native/jni/src/dictionary/structure/v4/content/shortcut_dict_content.h
@@ -17,21 +17,21 @@
 #ifndef LATINIME_SHORTCUT_DICT_CONTENT_H
 #define LATINIME_SHORTCUT_DICT_CONTENT_H
 
-#include <cstdint>
 #include <cstdio>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/v4/content/sparse_table_dict_content.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
 
 namespace latinime {
 
+class ReadWriteByteArrayView;
+
 class ShortcutDictContent : public SparseTableDictContent {
  public:
-    ShortcutDictContent(uint8_t *const *buffers, const int *bufferSizes)
-            : SparseTableDictContent(buffers, bufferSizes,
-                      Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE,
+    ShortcutDictContent(const ReadWriteByteArrayView *const buffers)
+            : SparseTableDictContent(buffers, Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE,
                       Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_DATA_SIZE) {}
 
     ShortcutDictContent()
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h b/native/jni/src/dictionary/structure/v4/content/single_dict_content.h
index 921774181..6faa9a28b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
+++ b/native/jni/src/dictionary/structure/v4/content/single_dict_content.h
@@ -17,22 +17,21 @@
 #ifndef LATINIME_SINGLE_DICT_CONTENT_H
 #define LATINIME_SINGLE_DICT_CONTENT_H
 
-#include <cstdint>
 #include <cstdio>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
 
 class SingleDictContent {
  public:
-    SingleDictContent(uint8_t *const buffer, const int bufferSize)
-            : mExpandableContentBuffer(ReadWriteByteArrayView(buffer, bufferSize),
-                      BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE) {}
+    SingleDictContent(const ReadWriteByteArrayView buffer)
+            : mExpandableContentBuffer(buffer,
+                    BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE) {}
 
     SingleDictContent()
             : mExpandableContentBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE) {}
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp b/native/jni/src/dictionary/structure/v4/content/sparse_table_dict_content.cpp
index 896ce6bd2..685365f36 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
+++ b/native/jni/src/dictionary/structure/v4/content/sparse_table_dict_content.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h"
+#include "dictionary/structure/v4/content/sparse_table_dict_content.h"
 
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h b/native/jni/src/dictionary/structure/v4/content/sparse_table_dict_content.h
index c98dd11fd..6245abc8e 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h
+++ b/native/jni/src/dictionary/structure/v4/content/sparse_table_dict_content.h
@@ -17,13 +17,12 @@
 #ifndef LATINIME_SPARSE_TABLE_DICT_CONTENT_H
 #define LATINIME_SPARSE_TABLE_DICT_CONTENT_H
 
-#include <cstdint>
 #include <cstdio>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/sparse_table.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/sparse_table.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
@@ -31,19 +30,13 @@ namespace latinime {
 // TODO: Support multiple contents.
 class SparseTableDictContent {
  public:
-    AK_FORCE_INLINE SparseTableDictContent(uint8_t *const *buffers, const int *bufferSizes,
+    AK_FORCE_INLINE SparseTableDictContent(const ReadWriteByteArrayView *const buffers,
             const int sparseTableBlockSize, const int sparseTableDataSize)
-            : mExpandableLookupTableBuffer(
-                      ReadWriteByteArrayView(buffers[LOOKUP_TABLE_BUFFER_INDEX],
-                              bufferSizes[LOOKUP_TABLE_BUFFER_INDEX]),
+            : mExpandableLookupTableBuffer(buffers[LOOKUP_TABLE_BUFFER_INDEX],
                       BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-              mExpandableAddressTableBuffer(
-                      ReadWriteByteArrayView(buffers[ADDRESS_TABLE_BUFFER_INDEX],
-                              bufferSizes[ADDRESS_TABLE_BUFFER_INDEX]),
+              mExpandableAddressTableBuffer(buffers[ADDRESS_TABLE_BUFFER_INDEX],
                       BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-              mExpandableContentBuffer(
-                      ReadWriteByteArrayView(buffers[CONTENT_BUFFER_INDEX],
-                              bufferSizes[CONTENT_BUFFER_INDEX]),
+              mExpandableContentBuffer(buffers[CONTENT_BUFFER_INDEX],
                       BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
               mAddressLookupTable(&mExpandableLookupTableBuffer, &mExpandableAddressTableBuffer,
                       sparseTableBlockSize, sparseTableDataSize) {}
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp b/native/jni/src/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
index cf238ee5f..5503151fd 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
+++ b/native/jni/src/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
@@ -14,10 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
@@ -34,7 +33,7 @@ int TerminalPositionLookupTable::getTerminalPtNodePosition(const int terminalId)
 bool TerminalPositionLookupTable::setTerminalPtNodePosition(
         const int terminalId, const int terminalPtNodePos) {
     if (terminalId < 0) {
-        return NOT_A_DICT_POS;
+        return false;
     }
     while (terminalId >= mSize) {
         // Write new entry.
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h b/native/jni/src/dictionary/structure/v4/content/terminal_position_lookup_table.h
index b2262bf1e..f45ceb52d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
+++ b/native/jni/src/dictionary/structure/v4/content/terminal_position_lookup_table.h
@@ -17,13 +17,13 @@
 #ifndef LATINIME_TERMINAL_POSITION_LOOKUP_TABLE_H
 #define LATINIME_TERMINAL_POSITION_LOOKUP_TABLE_H
 
-#include <cstdint>
 #include <cstdio>
 #include <unordered_map>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/v4/content/single_dict_content.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
@@ -31,8 +31,8 @@ class TerminalPositionLookupTable : public SingleDictContent {
  public:
     typedef std::unordered_map<int, int> TerminalIdMap;
 
-    TerminalPositionLookupTable(uint8_t *const buffer, const int bufferSize)
-            : SingleDictContent(buffer, bufferSize),
+    TerminalPositionLookupTable(const ReadWriteByteArrayView buffer)
+            : SingleDictContent(buffer),
               mSize(getBuffer()->getTailPosition()
                       / Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE) {}
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h b/native/jni/src/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
index 790273541..25ab22543 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
+++ b/native/jni/src/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
@@ -18,10 +18,10 @@
 #define LATINIME_VER4_SHORTCUT_LIST_POLICY_H
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/interface/dictionary_shortcuts_structure_policy.h"
+#include "dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "dictionary/structure/v4/content/shortcut_dict_content.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp b/native/jni/src/dictionary/structure/v4/ver4_dict_buffers.cpp
index 3c8008dc4..b0a82839b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_dict_buffers.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
 
 #include <cerrno>
 #include <cstring>
@@ -23,9 +23,9 @@
 #include <sys/types.h>
 #include <vector>
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/file_utils.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
@@ -45,16 +45,13 @@ namespace latinime {
     if (!bodyBuffer) {
         return Ver4DictBuffersPtr(nullptr);
     }
-    std::vector<uint8_t *> buffers;
-    std::vector<int> bufferSizes;
+    std::vector<ReadWriteByteArrayView> buffers;
     const ReadWriteByteArrayView buffer = bodyBuffer->getReadWriteByteArrayView();
     int position = 0;
     while (position < static_cast<int>(buffer.size())) {
         const int bufferSize = ByteArrayUtils::readUint32AndAdvancePosition(
                 buffer.data(), &position);
-        const ReadWriteByteArrayView subBuffer = buffer.subView(position, bufferSize);
-        buffers.push_back(subBuffer.data());
-        bufferSizes.push_back(subBuffer.size());
+        buffers.push_back(buffer.subView(position, bufferSize));
         position += bufferSize;
         if (bufferSize < 0 || position < 0 || position > static_cast<int>(buffer.size())) {
             AKLOGE("The dict body file is corrupted.");
@@ -66,7 +63,7 @@ namespace latinime {
         return Ver4DictBuffersPtr(nullptr);
     }
     return Ver4DictBuffersPtr(new Ver4DictBuffers(std::move(headerBuffer), std::move(bodyBuffer),
-            formatVersion, buffers, bufferSizes));
+            formatVersion, buffers));
 }
 
 bool Ver4DictBuffers::flushHeaderAndDictBuffers(const char *const dictDirPath,
@@ -162,11 +159,6 @@ bool Ver4DictBuffers::flushDictBuffers(FILE *const file) const {
         AKLOGE("Language model dict content cannot be written.");
         return false;
     }
-    // Write bigram dict content.
-    if (!mBigramDictContent.flushToFile(file)) {
-        AKLOGE("Bigram dict content cannot be written.");
-        return false;
-    }
     // Write shortcut dict content.
     if (!mShortcutDictContent.flushToFile(file)) {
         AKLOGE("Shortcut dict content cannot be written.");
@@ -178,29 +170,18 @@ bool Ver4DictBuffers::flushDictBuffers(FILE *const file) const {
 Ver4DictBuffers::Ver4DictBuffers(MmappedBuffer::MmappedBufferPtr &&headerBuffer,
         MmappedBuffer::MmappedBufferPtr &&bodyBuffer,
         const FormatUtils::FORMAT_VERSION formatVersion,
-        const std::vector<uint8_t *> &contentBuffers, const std::vector<int> &contentBufferSizes)
+        const std::vector<ReadWriteByteArrayView> &contentBuffers)
         : mHeaderBuffer(std::move(headerBuffer)), mDictBuffer(std::move(bodyBuffer)),
           mHeaderPolicy(mHeaderBuffer->getReadOnlyByteArrayView().data(), formatVersion),
           mExpandableHeaderBuffer(mHeaderBuffer->getReadWriteByteArrayView(),
                   BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-          mExpandableTrieBuffer(
-                  ReadWriteByteArrayView(contentBuffers[Ver4DictConstants::TRIE_BUFFER_INDEX],
-                          contentBufferSizes[Ver4DictConstants::TRIE_BUFFER_INDEX]),
+          mExpandableTrieBuffer(contentBuffers[Ver4DictConstants::TRIE_BUFFER_INDEX],
                   BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
           mTerminalPositionLookupTable(
-                  contentBuffers[Ver4DictConstants::TERMINAL_ADDRESS_LOOKUP_TABLE_BUFFER_INDEX],
-                  contentBufferSizes[
-                          Ver4DictConstants::TERMINAL_ADDRESS_LOOKUP_TABLE_BUFFER_INDEX]),
-          mLanguageModelDictContent(
-                  ReadWriteByteArrayView(
-                          contentBuffers[Ver4DictConstants::LANGUAGE_MODEL_BUFFER_INDEX],
-                          contentBufferSizes[Ver4DictConstants::LANGUAGE_MODEL_BUFFER_INDEX]),
-                  mHeaderPolicy.hasHistoricalInfoOfWords()),
-          mBigramDictContent(&contentBuffers[Ver4DictConstants::BIGRAM_BUFFERS_INDEX],
-                  &contentBufferSizes[Ver4DictConstants::BIGRAM_BUFFERS_INDEX],
+                  contentBuffers[Ver4DictConstants::TERMINAL_ADDRESS_LOOKUP_TABLE_BUFFER_INDEX]),
+          mLanguageModelDictContent(&contentBuffers[Ver4DictConstants::LANGUAGE_MODEL_BUFFER_INDEX],
                   mHeaderPolicy.hasHistoricalInfoOfWords()),
-          mShortcutDictContent(&contentBuffers[Ver4DictConstants::SHORTCUT_BUFFERS_INDEX],
-                  &contentBufferSizes[Ver4DictConstants::SHORTCUT_BUFFERS_INDEX]),
+          mShortcutDictContent(&contentBuffers[Ver4DictConstants::SHORTCUT_BUFFERS_INDEX]),
           mIsUpdatable(mDictBuffer->isUpdatable()) {}
 
 Ver4DictBuffers::Ver4DictBuffers(const HeaderPolicy *const headerPolicy, const int maxTrieSize)
@@ -208,7 +189,6 @@ Ver4DictBuffers::Ver4DictBuffers(const HeaderPolicy *const headerPolicy, const i
           mExpandableHeaderBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
           mExpandableTrieBuffer(maxTrieSize), mTerminalPositionLookupTable(),
           mLanguageModelDictContent(headerPolicy->hasHistoricalInfoOfWords()),
-          mBigramDictContent(headerPolicy->hasHistoricalInfoOfWords()), mShortcutDictContent(),
-          mIsUpdatable(true) {}
+          mShortcutDictContent(),  mIsUpdatable(true) {}
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h b/native/jni/src/dictionary/structure/v4/ver4_dict_buffers.h
index 68027dcb8..c8270c93c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_dict_buffers.h
@@ -21,14 +21,13 @@
 #include <memory>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/v4/content/language_model_dict_content.h"
+#include "dictionary/structure/v4/content/shortcut_dict_content.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/mmapped_buffer.h"
 
 namespace latinime {
 
@@ -53,7 +52,6 @@ class Ver4DictBuffers {
         return mExpandableTrieBuffer.isNearSizeLimit()
                 || mTerminalPositionLookupTable.isNearSizeLimit()
                 || mLanguageModelDictContent.isNearSizeLimit()
-                || mBigramDictContent.isNearSizeLimit()
                 || mShortcutDictContent.isNearSizeLimit();
     }
 
@@ -89,14 +87,6 @@ class Ver4DictBuffers {
         return &mLanguageModelDictContent;
     }
 
-    AK_FORCE_INLINE BigramDictContent *getMutableBigramDictContent() {
-        return &mBigramDictContent;
-    }
-
-    AK_FORCE_INLINE const BigramDictContent *getBigramDictContent() const {
-        return &mBigramDictContent;
-    }
-
     AK_FORCE_INLINE ShortcutDictContent *getMutableShortcutDictContent() {
         return &mShortcutDictContent;
     }
@@ -122,8 +112,7 @@ class Ver4DictBuffers {
     Ver4DictBuffers(MmappedBuffer::MmappedBufferPtr &&headerBuffer,
             MmappedBuffer::MmappedBufferPtr &&bodyBuffer,
             const FormatUtils::FORMAT_VERSION formatVersion,
-            const std::vector<uint8_t *> &contentBuffers,
-            const std::vector<int> &contentBufferSizes);
+            const std::vector<ReadWriteByteArrayView> &contentBuffers);
 
     Ver4DictBuffers(const HeaderPolicy *const headerPolicy, const int maxTrieSize);
 
@@ -136,7 +125,6 @@ class Ver4DictBuffers {
     BufferWithExtendableBuffer mExpandableTrieBuffer;
     TerminalPositionLookupTable mTerminalPositionLookupTable;
     LanguageModelDictContent mLanguageModelDictContent;
-    BigramDictContent mBigramDictContent;
     ShortcutDictContent mShortcutDictContent;
     const int mIsUpdatable;
 };
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp b/native/jni/src/dictionary/structure/v4/ver4_dict_constants.cpp
index 93d4e562d..fd6907824 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_dict_constants.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
 
 namespace latinime {
 
@@ -29,52 +29,44 @@ const int Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE = 1 * 1024 * 1024;
 
 // NUM_OF_BUFFERS_FOR_SINGLE_DICT_CONTENT for Trie and TerminalAddressLookupTable.
 // NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT for language model.
-// NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT for bigram and shortcut.
+// NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT for shortcut.
 const size_t Ver4DictConstants::NUM_OF_CONTENT_BUFFERS_IN_BODY_FILE =
         NUM_OF_BUFFERS_FOR_SINGLE_DICT_CONTENT * 2
                 + NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT
-                + NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT * 2;
+                + NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT;
 const int Ver4DictConstants::TRIE_BUFFER_INDEX = 0;
 const int Ver4DictConstants::TERMINAL_ADDRESS_LOOKUP_TABLE_BUFFER_INDEX =
         TRIE_BUFFER_INDEX + NUM_OF_BUFFERS_FOR_SINGLE_DICT_CONTENT;
 const int Ver4DictConstants::LANGUAGE_MODEL_BUFFER_INDEX =
         TERMINAL_ADDRESS_LOOKUP_TABLE_BUFFER_INDEX + NUM_OF_BUFFERS_FOR_SINGLE_DICT_CONTENT;
-const int Ver4DictConstants::BIGRAM_BUFFERS_INDEX =
-        LANGUAGE_MODEL_BUFFER_INDEX + NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT;
 const int Ver4DictConstants::SHORTCUT_BUFFERS_INDEX =
-        BIGRAM_BUFFERS_INDEX + NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT;
+        LANGUAGE_MODEL_BUFFER_INDEX + NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT;
 
 const int Ver4DictConstants::NOT_A_TERMINAL_ID = -1;
 const int Ver4DictConstants::PROBABILITY_SIZE = 1;
-const int Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE = 1;
+const int Ver4DictConstants::FLAGS_IN_LANGUAGE_MODEL_SIZE = 1;
 const int Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE = 3;
 const int Ver4DictConstants::NOT_A_TERMINAL_ADDRESS = 0;
 const int Ver4DictConstants::TERMINAL_ID_FIELD_SIZE = 4;
 const int Ver4DictConstants::TIME_STAMP_FIELD_SIZE = 4;
-const int Ver4DictConstants::WORD_LEVEL_FIELD_SIZE = 1;
-const int Ver4DictConstants::WORD_COUNT_FIELD_SIZE = 1;
+const int Ver4DictConstants::WORD_LEVEL_FIELD_SIZE = 0;
+const int Ver4DictConstants::WORD_COUNT_FIELD_SIZE = 2;
+
+const uint8_t Ver4DictConstants::FLAG_REPRESENTS_BEGINNING_OF_SENTENCE = 0x1;
+const uint8_t Ver4DictConstants::FLAG_NOT_A_VALID_ENTRY = 0x2;
+const uint8_t Ver4DictConstants::FLAG_NOT_A_WORD = 0x4;
+const uint8_t Ver4DictConstants::FLAG_BLACKLISTED = 0x8;
+const uint8_t Ver4DictConstants::FLAG_POSSIBLY_OFFENSIVE = 0x10;
 
-const int Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE = 16;
-const int Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE = 4;
 const int Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE = 64;
 const int Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_DATA_SIZE = 4;
 
-const int Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE = 3;
-// Unsigned int max value of BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE-byte is used for representing
-// invalid terminal ID in bigram lists.
-const int Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID =
-        (1 << (BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE * 8)) - 1;
-const int Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE = 1;
-const int Ver4DictConstants::BIGRAM_PROBABILITY_MASK = 0x0F;
-const int Ver4DictConstants::BIGRAM_IS_LINK_MASK = 0x80;
-const int Ver4DictConstants::BIGRAM_LARGE_PROBABILITY_FIELD_SIZE = 1;
-
 const int Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE = 1;
 const int Ver4DictConstants::SHORTCUT_PROBABILITY_MASK = 0x0F;
 const int Ver4DictConstants::SHORTCUT_HAS_NEXT_MASK = 0x80;
 
 const size_t Ver4DictConstants::NUM_OF_BUFFERS_FOR_SINGLE_DICT_CONTENT = 1;
 const size_t Ver4DictConstants::NUM_OF_BUFFERS_FOR_SPARSE_TABLE_DICT_CONTENT = 3;
-const size_t Ver4DictConstants::NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT = 1;
+const size_t Ver4DictConstants::NUM_OF_BUFFERS_FOR_LANGUAGE_MODEL_DICT_CONTENT = 2;
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h b/native/jni/src/dictionary/structure/v4/ver4_dict_constants.h
index 6950ca70f..13d7a5714 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_dict_constants.h
@@ -20,6 +20,7 @@
 #include "defines.h"
 
 #include <cstddef>
+#include <cstdint>
 
 namespace latinime {
 
@@ -41,27 +42,24 @@ class Ver4DictConstants {
 
     static const int NOT_A_TERMINAL_ID;
     static const int PROBABILITY_SIZE;
-    static const int FLAGS_IN_PROBABILITY_FILE_SIZE;
+    static const int FLAGS_IN_LANGUAGE_MODEL_SIZE;
     static const int TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE;
     static const int NOT_A_TERMINAL_ADDRESS;
     static const int TERMINAL_ID_FIELD_SIZE;
     static const int TIME_STAMP_FIELD_SIZE;
+    // TODO: Remove
     static const int WORD_LEVEL_FIELD_SIZE;
     static const int WORD_COUNT_FIELD_SIZE;
+    // Flags in probability entry.
+    static const uint8_t FLAG_REPRESENTS_BEGINNING_OF_SENTENCE;
+    static const uint8_t FLAG_NOT_A_VALID_ENTRY;
+    static const uint8_t FLAG_NOT_A_WORD;
+    static const uint8_t FLAG_BLACKLISTED;
+    static const uint8_t FLAG_POSSIBLY_OFFENSIVE;
 
-    static const int BIGRAM_ADDRESS_TABLE_BLOCK_SIZE;
-    static const int BIGRAM_ADDRESS_TABLE_DATA_SIZE;
     static const int SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE;
     static const int SHORTCUT_ADDRESS_TABLE_DATA_SIZE;
 
-    static const int BIGRAM_FLAGS_FIELD_SIZE;
-    static const int BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE;
-    static const int INVALID_BIGRAM_TARGET_TERMINAL_ID;
-    static const int BIGRAM_IS_LINK_MASK;
-    static const int BIGRAM_PROBABILITY_MASK;
-    // Used when bigram list has time stamp.
-    static const int BIGRAM_LARGE_PROBABILITY_FIELD_SIZE;
-
     static const int SHORTCUT_FLAGS_FIELD_SIZE;
     static const int SHORTCUT_PROBABILITY_MASK;
     static const int SHORTCUT_HAS_NEXT_MASK;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
index 731092efd..b38b03dcb 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
@@ -14,15 +14,16 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/v4/content/language_model_dict_content.h"
+#include "dictionary/structure/v4/content/probability_entry.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 
@@ -50,26 +51,17 @@ const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProce
     const int parentPos =
             DynamicPtReadingUtils::getParentPtNodePos(parentPosOffset, headPos);
     int codePoints[MAX_WORD_LENGTH];
-    const int codePonitCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
-            dictBuf, flags, MAX_WORD_LENGTH, codePoints, &pos);
+    // Code point table is not used for ver4 dictionaries.
+    const int codePointCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
+            dictBuf, flags, MAX_WORD_LENGTH, nullptr /* codePointTable */, codePoints, &pos);
     int terminalIdFieldPos = NOT_A_DICT_POS;
     int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
-    int probability = NOT_A_PROBABILITY;
     if (PatriciaTrieReadingUtils::isTerminal(flags)) {
         terminalIdFieldPos = pos;
         if (usesAdditionalBuffer) {
             terminalIdFieldPos += mBuffer->getOriginalBufferSize();
         }
         terminalId = Ver4PatriciaTrieReadingUtils::getTerminalIdAndAdvancePosition(dictBuf, &pos);
-        // TODO: Quit reading probability here.
-        const ProbabilityEntry probabilityEntry =
-                mLanguageModelDictContent->getProbabilityEntry(terminalId);
-        if (probabilityEntry.hasHistoricalInfo()) {
-            probability = ForgettingCurveUtils::decodeProbability(
-                    probabilityEntry.getHistoricalInfo(), mHeaderPolicy);
-        } else {
-            probability = probabilityEntry.getProbability();
-        }
     }
     int childrenPosFieldPos = pos;
     if (usesAdditionalBuffer) {
@@ -90,8 +82,8 @@ const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProce
         // The destination position is stored at the same place as the parent position.
         return fetchPtNodeInfoFromBufferAndProcessMovedPtNode(parentPos, newSiblingNodePos);
     } else {
-        return PtNodeParams(headPos, flags, parentPos, codePonitCount, codePoints,
-                terminalIdFieldPos, terminalId, probability, childrenPosFieldPos, childrenPos,
+        return PtNodeParams(headPos, flags, parentPos, codePointCount, codePoints,
+                terminalIdFieldPos, terminalId, NOT_A_PROBABILITY, childrenPosFieldPos, childrenPos,
                 newSiblingNodePos);
     }
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_reader.h
index a91ad5728..4e5ae3a89 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_reader.h
@@ -18,8 +18,8 @@
 #define LATINIME_VER4_PATRICIA_TRIE_NODE_READER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_reader.h"
 
 namespace latinime {
 
@@ -29,15 +29,12 @@ class LanguageModelDictContent;
 
 /*
  * This class is used for helping to read nodes of ver4 patricia trie. This class handles moved
- * node and reads node attributes including probability form language model.
+ * node and reads node attributes.
  */
 class Ver4PatriciaTrieNodeReader : public PtNodeReader {
  public:
-    Ver4PatriciaTrieNodeReader(const BufferWithExtendableBuffer *const buffer,
-            const LanguageModelDictContent *const languageModelDictContent,
-            const HeaderPolicy *const headerPolicy)
-            : mBuffer(buffer), mLanguageModelDictContent(languageModelDictContent),
-              mHeaderPolicy(headerPolicy) {}
+    explicit Ver4PatriciaTrieNodeReader(const BufferWithExtendableBuffer *const buffer)
+            : mBuffer(buffer) {}
 
     ~Ver4PatriciaTrieNodeReader() {}
 
@@ -50,8 +47,6 @@ class Ver4PatriciaTrieNodeReader : public PtNodeReader {
     DISALLOW_COPY_AND_ASSIGN(Ver4PatriciaTrieNodeReader);
 
     const BufferWithExtendableBuffer *const mBuffer;
-    const LanguageModelDictContent *const mLanguageModelDictContent;
-    const HeaderPolicy *const mHeaderPolicy;
 
     const PtNodeParams fetchPtNodeInfoFromBufferAndProcessMovedPtNode(const int ptNodePos,
             const int siblingNodePos) const;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
index 857222f5d..d974b50f4 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
@@ -14,20 +14,19 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
 
-#include "suggest/core/dictionary/property/unigram_property.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/structure/v4/content/probability_entry.h"
+#include "dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 namespace latinime {
 
@@ -62,6 +61,7 @@ bool Ver4PatriciaTrieNodeWriter::markPtNodeAsDeleted(
     }
 }
 
+// TODO: Quit using bigramLinkedNodePos.
 bool Ver4PatriciaTrieNodeWriter::markPtNodeAsMoved(
         const PtNodeParams *const toBeUpdatedPtNodeParams,
         const int movedPos, const int bigramLinkedNodePos) {
@@ -142,13 +142,9 @@ bool Ver4PatriciaTrieNodeWriter::updatePtNodeUnigramProperty(
     if (!toBeUpdatedPtNodeParams->isTerminal()) {
         return false;
     }
-    const ProbabilityEntry originalProbabilityEntry =
-            mBuffers->getLanguageModelDictContent()->getProbabilityEntry(
-                    toBeUpdatedPtNodeParams->getTerminalId());
-    const ProbabilityEntry probabilityEntry = createUpdatedEntryFrom(&originalProbabilityEntry,
-            unigramProperty);
+    const ProbabilityEntry probabilityEntryOfUnigramProperty = ProbabilityEntry(unigramProperty);
     return mBuffers->getMutableLanguageModelDictContent()->setProbabilityEntry(
-            toBeUpdatedPtNodeParams->getTerminalId(), &probabilityEntry);
+            toBeUpdatedPtNodeParams->getTerminalId(), &probabilityEntryOfUnigramProperty);
 }
 
 bool Ver4PatriciaTrieNodeWriter::updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(
@@ -160,29 +156,15 @@ bool Ver4PatriciaTrieNodeWriter::updatePtNodeProbabilityAndGetNeedsToKeepPtNodeA
     const ProbabilityEntry originalProbabilityEntry =
             mBuffers->getLanguageModelDictContent()->getProbabilityEntry(
                     toBeUpdatedPtNodeParams->getTerminalId());
-    if (originalProbabilityEntry.hasHistoricalInfo()) {
-        const HistoricalInfo historicalInfo = ForgettingCurveUtils::createHistoricalInfoToSave(
-                originalProbabilityEntry.getHistoricalInfo(), mHeaderPolicy);
-        const ProbabilityEntry probabilityEntry =
-                originalProbabilityEntry.createEntryWithUpdatedHistoricalInfo(&historicalInfo);
-        if (!mBuffers->getMutableLanguageModelDictContent()->setProbabilityEntry(
-                toBeUpdatedPtNodeParams->getTerminalId(), &probabilityEntry)) {
-            AKLOGE("Cannot write updated probability entry. terminalId: %d",
-                    toBeUpdatedPtNodeParams->getTerminalId());
-            return false;
-        }
-        const bool isValid = ForgettingCurveUtils::needsToKeep(&historicalInfo, mHeaderPolicy);
-        if (!isValid) {
-            if (!markPtNodeAsWillBecomeNonTerminal(toBeUpdatedPtNodeParams)) {
-                AKLOGE("Cannot mark PtNode as willBecomeNonTerminal.");
-                return false;
-            }
-        }
-        *outNeedsToKeepPtNode = isValid;
-    } else {
-        // No need to update probability.
+    if (originalProbabilityEntry.isValid()) {
         *outNeedsToKeepPtNode = true;
+        return true;
     }
+    if (!markPtNodeAsWillBecomeNonTerminal(toBeUpdatedPtNodeParams)) {
+        AKLOGE("Cannot mark PtNode as willBecomeNonTerminal.");
+        return false;
+    }
+    *outNeedsToKeepPtNode = false;
     return true;
 }
 
@@ -205,7 +187,6 @@ bool Ver4PatriciaTrieNodeWriter::writePtNodeAndAdvancePosition(
             ptNodeWritingPos);
 }
 
-
 bool Ver4PatriciaTrieNodeWriter::writeNewTerminalPtNodeAndAdvancePosition(
         const PtNodeParams *const ptNodeParams, const UnigramProperty *const unigramProperty,
         int *const ptNodeWritingPos) {
@@ -216,31 +197,43 @@ bool Ver4PatriciaTrieNodeWriter::writeNewTerminalPtNodeAndAdvancePosition(
     }
     // Write probability.
     ProbabilityEntry newProbabilityEntry;
-    const ProbabilityEntry probabilityEntryToWrite = createUpdatedEntryFrom(
-            &newProbabilityEntry, unigramProperty);
+    const ProbabilityEntry probabilityEntryOfUnigramProperty = ProbabilityEntry(unigramProperty);
     return mBuffers->getMutableLanguageModelDictContent()->setProbabilityEntry(
-            terminalId, &probabilityEntryToWrite);
+            terminalId, &probabilityEntryOfUnigramProperty);
 }
 
+// TODO: Support counting ngram entries.
 bool Ver4PatriciaTrieNodeWriter::addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
-        const BigramProperty *const bigramProperty, bool *const outAddedNewBigram) {
-    if (!mBigramPolicy->addNewEntry(prevWordIds[0], wordId, bigramProperty, outAddedNewBigram)) {
-        AKLOGE("Cannot add new bigram entry. terminalId: %d, targetTerminalId: %d",
-                prevWordIds[0], wordId);
+        const NgramProperty *const ngramProperty, bool *const outAddedNewBigram) {
+    LanguageModelDictContent *const languageModelDictContent =
+            mBuffers->getMutableLanguageModelDictContent();
+    const ProbabilityEntry probabilityEntry =
+            languageModelDictContent->getNgramProbabilityEntry(prevWordIds, wordId);
+    const ProbabilityEntry probabilityEntryOfNgramProperty(ngramProperty);
+    if (!languageModelDictContent->setNgramProbabilityEntry(
+            prevWordIds, wordId, &probabilityEntryOfNgramProperty)) {
+        AKLOGE("Cannot add new ngram entry. prevWordId[0]: %d, prevWordId.size(): %zd, wordId: %d",
+                prevWordIds[0], prevWordIds.size(), wordId);
         return false;
     }
+    if (!probabilityEntry.isValid() && outAddedNewBigram) {
+        *outAddedNewBigram = true;
+    }
     return true;
 }
 
 bool Ver4PatriciaTrieNodeWriter::removeNgramEntry(const WordIdArrayView prevWordIds,
         const int wordId) {
-    return mBigramPolicy->removeEntry(prevWordIds[0], wordId);
+    LanguageModelDictContent *const languageModelDictContent =
+            mBuffers->getMutableLanguageModelDictContent();
+    return languageModelDictContent->removeNgramProbabilityEntry(prevWordIds, wordId);
 }
 
+// TODO: Remove when we stop supporting v402 format.
 bool Ver4PatriciaTrieNodeWriter::updateAllBigramEntriesAndDeleteUselessEntries(
             const PtNodeParams *const sourcePtNodeParams, int *const outBigramEntryCount) {
-    return mBigramPolicy->updateAllBigramEntriesAndDeleteUselessEntries(
-            sourcePtNodeParams->getTerminalId(), outBigramEntryCount);
+    // Do nothing.
+    return true;
 }
 
 bool Ver4PatriciaTrieNodeWriter::updateAllPositionFields(
@@ -275,12 +268,6 @@ bool Ver4PatriciaTrieNodeWriter::updateAllPositionFields(
     if (!updateChildrenPosition(toBeUpdatedPtNodeParams, childrenPos)) {
         return false;
     }
-
-    // Counts bigram entries.
-    if (outBigramEntryCount) {
-        *outBigramEntryCount = mBigramPolicy->getBigramEntryConut(
-                toBeUpdatedPtNodeParams->getTerminalId());
-    }
     return true;
 }
 
@@ -289,7 +276,7 @@ bool Ver4PatriciaTrieNodeWriter::addShortcutTarget(const PtNodeParams *const ptN
         const int shortcutProbability) {
     if (!mShortcutPolicy->addNewShortcut(ptNodeParams->getTerminalId(),
             targetCodePoints, targetCodePointCount, shortcutProbability)) {
-        AKLOGE("Cannot add new shortuct entry. terminalId: %d", ptNodeParams->getTerminalId());
+        AKLOGE("Cannot add new shortcut entry. terminalId: %d", ptNodeParams->getTerminalId());
         return false;
     }
     return true;
@@ -346,37 +333,17 @@ bool Ver4PatriciaTrieNodeWriter::writePtNodeAndGetTerminalIdAndAdvancePosition(
             ptNodeParams->getChildrenPos(), ptNodeWritingPos)) {
         return false;
     }
-    return updatePtNodeFlags(nodePos, ptNodeParams->isBlacklisted(), ptNodeParams->isNotAWord(),
-            isTerminal, ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
-}
-
-const ProbabilityEntry Ver4PatriciaTrieNodeWriter::createUpdatedEntryFrom(
-        const ProbabilityEntry *const originalProbabilityEntry,
-        const UnigramProperty *const unigramProperty) const {
-    // TODO: Consolidate historical info and probability.
-    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
-        const HistoricalInfo historicalInfoForUpdate(unigramProperty->getTimestamp(),
-                unigramProperty->getLevel(), unigramProperty->getCount());
-        const HistoricalInfo updatedHistoricalInfo =
-                ForgettingCurveUtils::createUpdatedHistoricalInfo(
-                        originalProbabilityEntry->getHistoricalInfo(),
-                        unigramProperty->getProbability(), &historicalInfoForUpdate, mHeaderPolicy);
-        return originalProbabilityEntry->createEntryWithUpdatedHistoricalInfo(
-                &updatedHistoricalInfo);
-    } else {
-        return originalProbabilityEntry->createEntryWithUpdatedProbability(
-                unigramProperty->getProbability());
-    }
+    return updatePtNodeFlags(nodePos, isTerminal,
+            ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
 }
 
-bool Ver4PatriciaTrieNodeWriter::updatePtNodeFlags(const int ptNodePos,
-        const bool isBlacklisted, const bool isNotAWord, const bool isTerminal,
+bool Ver4PatriciaTrieNodeWriter::updatePtNodeFlags(const int ptNodePos, const bool isTerminal,
         const bool hasMultipleChars) {
     // Create node flags and write them.
     PatriciaTrieReadingUtils::NodeFlags nodeFlags =
-            PatriciaTrieReadingUtils::createAndGetFlags(isBlacklisted, isNotAWord, isTerminal,
-                    false /* hasShortcutTargets */, false /* hasBigrams */, hasMultipleChars,
-                    CHILDREN_POSITION_FIELD_SIZE);
+            PatriciaTrieReadingUtils::createAndGetFlags(false /* isNotAWord */,
+                    false /* isPossiblyOffensive */, isTerminal, false /* hasShortcutTargets */,
+                    false /* hasBigrams */, hasMultipleChars, CHILDREN_POSITION_FIELD_SIZE);
     if (!DynamicPtWritingUtils::writeFlags(mTrieBuffer, nodeFlags, ptNodePos)) {
         AKLOGE("Cannot write PtNode flags. flags: %x, pos: %d", nodeFlags, ptNodePos);
         return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
index 6703dba04..55856110b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
@@ -18,16 +18,15 @@
 #define LATINIME_VER4_PATRICIA_TRIE_NODE_WRITER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/pt_common/pt_node_params.h"
+#include "dictionary/structure/pt_common/pt_node_writer.h"
+#include "dictionary/structure/v4/content/probability_entry.h"
 
 namespace latinime {
 
 class BufferWithExtendableBuffer;
 class HeaderPolicy;
-class Ver4BigramListPolicy;
 class Ver4DictBuffers;
 class Ver4PatriciaTrieNodeReader;
 class Ver4PtNodeArrayReader;
@@ -39,13 +38,11 @@ class Ver4ShortcutListPolicy;
 class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
  public:
     Ver4PatriciaTrieNodeWriter(BufferWithExtendableBuffer *const trieBuffer,
-            Ver4DictBuffers *const buffers, const HeaderPolicy *const headerPolicy,
-            const PtNodeReader *const ptNodeReader,
+            Ver4DictBuffers *const buffers, const PtNodeReader *const ptNodeReader,
             const PtNodeArrayReader *const ptNodeArrayReader,
-            Ver4BigramListPolicy *const bigramPolicy, Ver4ShortcutListPolicy *const shortcutPolicy)
-            : mTrieBuffer(trieBuffer), mBuffers(buffers), mHeaderPolicy(headerPolicy),
-              mReadingHelper(ptNodeReader, ptNodeArrayReader), mBigramPolicy(bigramPolicy),
-              mShortcutPolicy(shortcutPolicy) {}
+            Ver4ShortcutListPolicy *const shortcutPolicy)
+            : mTrieBuffer(trieBuffer), mBuffers(buffers),
+              mReadingHelper(ptNodeReader, ptNodeArrayReader), mShortcutPolicy(shortcutPolicy) {}
 
     virtual ~Ver4PatriciaTrieNodeWriter() {}
 
@@ -76,7 +73,7 @@ class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
             const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos);
 
     virtual bool addNgramEntry(const WordIdArrayView prevWordIds, const int wordId,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
+            const NgramProperty *const ngramProperty, bool *const outAddedNewEntry);
 
     virtual bool removeNgramEntry(const WordIdArrayView prevWordIds, const int wordId);
 
@@ -98,23 +95,13 @@ class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
             const PtNodeParams *const ptNodeParams, int *const outTerminalId,
             int *const ptNodeWritingPos);
 
-    // Create updated probability entry using given unigram property. In addition to the
-    // probability, this method updates historical information if needed.
-    // TODO: Update flags belonging to the unigram property.
-    const ProbabilityEntry createUpdatedEntryFrom(
-            const ProbabilityEntry *const originalProbabilityEntry,
-            const UnigramProperty *const unigramProperty) const;
-
-    bool updatePtNodeFlags(const int ptNodePos, const bool isBlacklisted, const bool isNotAWord,
-            const bool isTerminal, const bool hasMultipleChars);
+    bool updatePtNodeFlags(const int ptNodePos, const bool isTerminal, const bool hasMultipleChars);
 
     static const int CHILDREN_POSITION_FIELD_SIZE;
 
     BufferWithExtendableBuffer *const mTrieBuffer;
     Ver4DictBuffers *const mBuffers;
-    const HeaderPolicy *const mHeaderPolicy;
     DynamicPtReadingHelper mReadingHelper;
-    Ver4BigramListPolicy *const mBigramPolicy;
     Ver4ShortcutListPolicy *const mShortcutPolicy;
 };
 } // namespace latinime
diff --git a/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_policy.cpp b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
new file mode 100644
index 000000000..1dbec5545
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
@@ -0,0 +1,603 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/structure/v4/ver4_patricia_trie_policy.h"
+
+#include <array>
+#include <vector>
+
+#include "suggest/core/dicnode/dic_node.h"
+#include "suggest/core/dicnode/dic_node_vector.h"
+#include "dictionary/interface/ngram_listener.h"
+#include "dictionary/property/ngram_context.h"
+#include "dictionary/property/ngram_property.h"
+#include "dictionary/property/unigram_property.h"
+#include "dictionary/property/word_property.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/utils/multi_bigram_map.h"
+#include "dictionary/utils/probability_utils.h"
+#include "utils/ngram_utils.h"
+
+namespace latinime {
+
+// Note that there are corresponding definitions in Java side in BinaryDictionaryTests and
+// BinaryDictionaryDecayingTests.
+const char *const Ver4PatriciaTriePolicy::UNIGRAM_COUNT_QUERY = "UNIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::BIGRAM_COUNT_QUERY = "BIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::MAX_UNIGRAM_COUNT_QUERY = "MAX_UNIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::MAX_BIGRAM_COUNT_QUERY = "MAX_BIGRAM_COUNT";
+const int Ver4PatriciaTriePolicy::MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS = 1024;
+const int Ver4PatriciaTriePolicy::MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS =
+        Ver4DictConstants::MAX_DICTIONARY_SIZE - MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
+
+void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNode,
+        DicNodeVector *const childDicNodes) const {
+    if (!dicNode->hasChildren()) {
+        return;
+    }
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(dicNode->getChildrenPtNodeArrayPos());
+    while (!readingHelper.isEnd()) {
+        const PtNodeParams ptNodeParams = readingHelper.getPtNodeParams();
+        if (!ptNodeParams.isValid()) {
+            break;
+        }
+        const bool isTerminal = ptNodeParams.isTerminal() && !ptNodeParams.isDeleted();
+        const int wordId = isTerminal ? ptNodeParams.getTerminalId() : NOT_A_WORD_ID;
+        childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getChildrenPos(),
+                wordId, ptNodeParams.getCodePointArrayView());
+        readingHelper.readNextSiblingNode(ptNodeParams);
+    }
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+    }
+}
+
+int Ver4PatriciaTriePolicy::getCodePointsAndReturnCodePointCount(const int wordId,
+        const int maxCodePointCount, int *const outCodePoints) const {
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    const int ptNodePos =
+            mBuffers->getTerminalPositionLookupTable()->getTerminalPtNodePosition(wordId);
+    readingHelper.initWithPtNodePos(ptNodePos);
+    const int codePointCount =  readingHelper.getCodePointsAndReturnCodePointCount(
+            maxCodePointCount, outCodePoints);
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in getCodePointsAndProbabilityAndReturnCodePointCount().");
+    }
+    return codePointCount;
+}
+
+int Ver4PatriciaTriePolicy::getWordId(const CodePointArrayView wordCodePoints,
+        const bool forceLowerCaseSearch) const {
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(getRootPosition());
+    const int ptNodePos = readingHelper.getTerminalPtNodePositionOfWord(wordCodePoints.data(),
+            wordCodePoints.size(), forceLowerCaseSearch);
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+    }
+    if (ptNodePos == NOT_A_DICT_POS) {
+        return NOT_A_WORD_ID;
+    }
+    const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
+    if (ptNodeParams.isDeleted()) {
+        return NOT_A_WORD_ID;
+    }
+    return ptNodeParams.getTerminalId();
+}
+
+const WordAttributes Ver4PatriciaTriePolicy::getWordAttributesInContext(
+        const WordIdArrayView prevWordIds, const int wordId,
+        MultiBigramMap *const multiBigramMap) const {
+    if (wordId == NOT_A_WORD_ID) {
+        return WordAttributes();
+    }
+    return mBuffers->getLanguageModelDictContent()->getWordAttributes(prevWordIds, wordId,
+            false /* mustMatchAllPrevWords */, mHeaderPolicy);
+}
+
+int Ver4PatriciaTriePolicy::getProbabilityOfWord(const WordIdArrayView prevWordIds,
+        const int wordId) const {
+    if (wordId == NOT_A_WORD_ID || prevWordIds.contains(NOT_A_WORD_ID)) {
+        return NOT_A_PROBABILITY;
+    }
+    const WordAttributes wordAttributes =
+            mBuffers->getLanguageModelDictContent()->getWordAttributes(prevWordIds, wordId,
+                    true /* mustMatchAllPrevWords */, mHeaderPolicy);
+    if (wordAttributes.isBlacklisted() || wordAttributes.isNotAWord()) {
+        return NOT_A_PROBABILITY;
+    }
+    return wordAttributes.getProbability();
+}
+
+BinaryDictionaryShortcutIterator Ver4PatriciaTriePolicy::getShortcutIterator(
+        const int wordId) const {
+    const int shortcutPos = getShortcutPositionOfWord(wordId);
+    return BinaryDictionaryShortcutIterator(&mShortcutPolicy, shortcutPos);
+}
+
+void Ver4PatriciaTriePolicy::iterateNgramEntries(const WordIdArrayView prevWordIds,
+        NgramListener *const listener) const {
+    if (prevWordIds.empty()) {
+        return;
+    }
+    const auto languageModelDictContent = mBuffers->getLanguageModelDictContent();
+    for (size_t i = 1; i <= prevWordIds.size(); ++i) {
+        for (const auto entry : languageModelDictContent->getProbabilityEntries(
+                prevWordIds.limit(i))) {
+            const ProbabilityEntry &probabilityEntry = entry.getProbabilityEntry();
+            if (!probabilityEntry.isValid()) {
+                continue;
+            }
+            int probability = NOT_A_PROBABILITY;
+            if (probabilityEntry.hasHistoricalInfo()) {
+                // TODO: Quit checking count here.
+                // If count <= 1, the word can be an invaild word. The actual probability should
+                // be checked using getWordAttributesInContext() in onVisitEntry().
+                probability = probabilityEntry.getHistoricalInfo()->getCount() <= 1 ?
+                        NOT_A_PROBABILITY : 0;
+            } else {
+                probability = probabilityEntry.getProbability();
+            }
+            listener->onVisitEntry(probability, entry.getWordId());
+        }
+    }
+}
+
+int Ver4PatriciaTriePolicy::getShortcutPositionOfWord(const int wordId) const {
+    if (wordId == NOT_A_WORD_ID) {
+        return NOT_A_DICT_POS;
+    }
+    const int ptNodePos =
+            mBuffers->getTerminalPositionLookupTable()->getTerminalPtNodePosition(wordId);
+    const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
+    if (ptNodeParams.isDeleted()) {
+        return NOT_A_DICT_POS;
+    }
+    return mBuffers->getShortcutDictContent()->getShortcutListHeadPos(
+            ptNodeParams.getTerminalId());
+}
+
+bool Ver4PatriciaTriePolicy::addUnigramEntry(const CodePointArrayView wordCodePoints,
+        const UnigramProperty *const unigramProperty) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: addUnigramEntry() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    if (wordCodePoints.size() > MAX_WORD_LENGTH) {
+        AKLOGE("The word is too long to insert to the dictionary, length: %zd",
+                wordCodePoints.size());
+        return false;
+    }
+    for (const auto &shortcut : unigramProperty->getShortcuts()) {
+        if (shortcut.getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
+            AKLOGE("One of shortcut targets is too long to insert to the dictionary, length: %zd",
+                    shortcut.getTargetCodePoints()->size());
+            return false;
+        }
+    }
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(getRootPosition());
+    bool addedNewUnigram = false;
+    int codePointsToAdd[MAX_WORD_LENGTH];
+    int codePointCountToAdd = wordCodePoints.size();
+    memmove(codePointsToAdd, wordCodePoints.data(), sizeof(int) * codePointCountToAdd);
+    if (unigramProperty->representsBeginningOfSentence()) {
+        codePointCountToAdd = CharUtils::attachBeginningOfSentenceMarker(codePointsToAdd,
+                codePointCountToAdd, MAX_WORD_LENGTH);
+    }
+    if (codePointCountToAdd <= 0) {
+        return false;
+    }
+    const CodePointArrayView codePointArrayView(codePointsToAdd, codePointCountToAdd);
+    if (mUpdatingHelper.addUnigramWord(&readingHelper, codePointArrayView, unigramProperty,
+            &addedNewUnigram)) {
+        if (addedNewUnigram && !unigramProperty->representsBeginningOfSentence()) {
+            mEntryCounters.incrementNgramCount(NgramType::Unigram);
+        }
+        if (unigramProperty->getShortcuts().size() > 0) {
+            // Add shortcut target.
+            const int wordId = getWordId(codePointArrayView, false /* forceLowerCaseSearch */);
+            if (wordId == NOT_A_WORD_ID) {
+                AKLOGE("Cannot find word id to add shortcut target.");
+                return false;
+            }
+            const int wordPos =
+                    mBuffers->getTerminalPositionLookupTable()->getTerminalPtNodePosition(wordId);
+            for (const auto &shortcut : unigramProperty->getShortcuts()) {
+                if (!mUpdatingHelper.addShortcutTarget(wordPos,
+                        CodePointArrayView(*shortcut.getTargetCodePoints()),
+                        shortcut.getProbability())) {
+                    AKLOGE("Cannot add new shortcut target. PtNodePos: %d, length: %zd, "
+                            "probability: %d", wordPos, shortcut.getTargetCodePoints()->size(),
+                            shortcut.getProbability());
+                    return false;
+                }
+            }
+        }
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::removeUnigramEntry(const CodePointArrayView wordCodePoints) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: removeUnigramEntry() is called for non-updatable dictionary.");
+        return false;
+    }
+    const int wordId = getWordId(wordCodePoints, false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
+        return false;
+    }
+    const int ptNodePos =
+            mBuffers->getTerminalPositionLookupTable()->getTerminalPtNodePosition(wordId);
+    const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
+    if (!mNodeWriter.markPtNodeAsDeleted(&ptNodeParams)) {
+        AKLOGE("Cannot remove unigram. ptNodePos: %d", ptNodePos);
+        return false;
+    }
+    if (!mBuffers->getMutableLanguageModelDictContent()->removeProbabilityEntry(wordId)) {
+        return false;
+    }
+    if (!ptNodeParams.representsNonWordInfo()) {
+        mEntryCounters.decrementNgramCount(NgramType::Unigram);
+    }
+    return true;
+}
+
+bool Ver4PatriciaTriePolicy::addNgramEntry(const NgramProperty *const ngramProperty) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: addNgramEntry() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    const NgramContext *const ngramContext = ngramProperty->getNgramContext();
+    if (!ngramContext->isValid()) {
+        AKLOGE("Ngram context is not valid for adding n-gram entry to the dictionary.");
+        return false;
+    }
+    if (ngramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
+        AKLOGE("The word is too long to insert the ngram to the dictionary. "
+                "length: %zd", ngramProperty->getTargetCodePoints()->size());
+        return false;
+    }
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(this, &prevWordIdArray,
+            false /* tryLowerCaseSearch */);
+    if (prevWordIds.empty()) {
+        return false;
+    }
+    for (size_t i = 0; i < prevWordIds.size(); ++i) {
+        if (prevWordIds[i] != NOT_A_WORD_ID) {
+            continue;
+        }
+        if (!ngramContext->isNthPrevWordBeginningOfSentence(i + 1 /* n */)) {
+            return false;
+        }
+        const UnigramProperty beginningOfSentenceUnigramProperty(
+                true /* representsBeginningOfSentence */, true /* isNotAWord */,
+                false /* isBlacklisted */, false /* isPossiblyOffensive */,
+                MAX_PROBABILITY /* probability */, HistoricalInfo());
+        if (!addUnigramEntry(ngramContext->getNthPrevWordCodePoints(1 /* n */),
+                &beginningOfSentenceUnigramProperty)) {
+            AKLOGE("Cannot add unigram entry for the beginning-of-sentence.");
+            return false;
+        }
+        // Refresh word ids.
+        ngramContext->getPrevWordIds(this, &prevWordIdArray, false /* tryLowerCaseSearch */);
+    }
+    const int wordId = getWordId(CodePointArrayView(*ngramProperty->getTargetCodePoints()),
+            false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
+        return false;
+    }
+    bool addedNewEntry = false;
+    if (mNodeWriter.addNgramEntry(prevWordIds, wordId, ngramProperty, &addedNewEntry)) {
+        if (addedNewEntry) {
+            mEntryCounters.incrementNgramCount(
+                    NgramUtils::getNgramTypeFromWordCount(prevWordIds.size() + 1));
+        }
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::removeNgramEntry(const NgramContext *const ngramContext,
+        const CodePointArrayView wordCodePoints) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: removeNgramEntry() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    if (!ngramContext->isValid()) {
+        AKLOGE("Ngram context is not valid for removing n-gram entry form the dictionary.");
+        return false;
+    }
+    if (wordCodePoints.size() > MAX_WORD_LENGTH) {
+        AKLOGE("word is too long to remove n-gram entry form the dictionary. length: %zd",
+                wordCodePoints.size());
+    }
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(this, &prevWordIdArray,
+            false /* tryLowerCaseSerch */);
+    if (prevWordIds.empty() || prevWordIds.contains(NOT_A_WORD_ID)) {
+        return false;
+    }
+    const int wordId = getWordId(wordCodePoints, false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
+        return false;
+    }
+    if (mNodeWriter.removeNgramEntry(prevWordIds, wordId)) {
+        mEntryCounters.decrementNgramCount(
+                NgramUtils::getNgramTypeFromWordCount(prevWordIds.size() + 1));
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::updateEntriesForWordWithNgramContext(
+        const NgramContext *const ngramContext, const CodePointArrayView wordCodePoints,
+        const bool isValidWord, const HistoricalInfo historicalInfo) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: updateEntriesForWordWithNgramContext() is called for non-updatable "
+                "dictionary.");
+        return false;
+    }
+    const bool updateAsAValidWord = ngramContext->isNthPrevWordBeginningOfSentence(1 /* n */) ?
+            false : isValidWord;
+    int wordId = getWordId(wordCodePoints, false /* tryLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
+        // The word is not in the dictionary.
+        const UnigramProperty unigramProperty(false /* representsBeginningOfSentence */,
+                false /* isNotAWord */, false /* isBlacklisted */, false /* isPossiblyOffensive */,
+                NOT_A_PROBABILITY, HistoricalInfo(historicalInfo.getTimestamp(), 0 /* level */,
+                0 /* count */));
+        if (!addUnigramEntry(wordCodePoints, &unigramProperty)) {
+            AKLOGE("Cannot add unigarm entry in updateEntriesForWordWithNgramContext().");
+            return false;
+        }
+        if (!isValidWord) {
+            return true;
+        }
+        wordId = getWordId(wordCodePoints, false /* tryLowerCaseSearch */);
+    }
+
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(this, &prevWordIdArray,
+            false /* tryLowerCaseSearch */);
+    if (ngramContext->isNthPrevWordBeginningOfSentence(1 /* n */)) {
+        if (prevWordIds.firstOrDefault(NOT_A_WORD_ID) == NOT_A_WORD_ID) {
+            const UnigramProperty beginningOfSentenceUnigramProperty(
+                    true /* representsBeginningOfSentence */,
+                    true /* isNotAWord */, false /* isPossiblyOffensive */, NOT_A_PROBABILITY,
+                    HistoricalInfo(historicalInfo.getTimestamp(), 0 /* level */, 0 /* count */));
+            if (!addUnigramEntry(ngramContext->getNthPrevWordCodePoints(1 /* n */),
+                    &beginningOfSentenceUnigramProperty)) {
+                AKLOGE("Cannot add BoS entry in updateEntriesForWordWithNgramContext().");
+                return false;
+            }
+            // Refresh word ids.
+            ngramContext->getPrevWordIds(this, &prevWordIdArray, false /* tryLowerCaseSearch */);
+        }
+        // Update entries for beginning of sentence.
+        if (!mBuffers->getMutableLanguageModelDictContent()->updateAllEntriesOnInputWord(
+                prevWordIds.skip(1 /* n */), prevWordIds[0], true /* isVaild */, historicalInfo,
+                mHeaderPolicy, &mEntryCounters)) {
+            return false;
+        }
+    }
+    if (!mBuffers->getMutableLanguageModelDictContent()->updateAllEntriesOnInputWord(prevWordIds,
+            wordId, updateAsAValidWord, historicalInfo, mHeaderPolicy, &mEntryCounters)) {
+        return false;
+    }
+    return true;
+}
+
+bool Ver4PatriciaTriePolicy::flush(const char *const filePath) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: flush() is called for non-updatable dictionary. filePath: %s", filePath);
+        return false;
+    }
+    if (!mWritingHelper.writeToDictFile(filePath, mEntryCounters.getEntryCounts())) {
+        AKLOGE("Cannot flush the dictionary to file.");
+        mIsCorrupted = true;
+        return false;
+    }
+    return true;
+}
+
+bool Ver4PatriciaTriePolicy::flushWithGC(const char *const filePath) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: flushWithGC() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (!mWritingHelper.writeToDictFileWithGC(getRootPosition(), filePath)) {
+        AKLOGE("Cannot flush the dictionary to file with GC.");
+        mIsCorrupted = true;
+        return false;
+    }
+    return true;
+}
+
+bool Ver4PatriciaTriePolicy::needsToRunGC(const bool mindsBlockByGC) const {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: needsToRunGC() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mBuffers->isNearSizeLimit()) {
+        // Additional buffer size is near the limit.
+        return true;
+    } else if (mHeaderPolicy->getExtendedRegionSize() + mDictBuffer->getUsedAdditionalBufferSize()
+            > Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE) {
+        // Total extended region size of the trie exceeds the limit.
+        return true;
+    } else if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS
+            && mDictBuffer->getUsedAdditionalBufferSize() > 0) {
+        // Needs to reduce dictionary size.
+        return true;
+    } else if (mHeaderPolicy->isDecayingDict()) {
+        return ForgettingCurveUtils::needsToDecay(mindsBlockByGC, mEntryCounters.getEntryCounts(),
+                mHeaderPolicy);
+    }
+    return false;
+}
+
+void Ver4PatriciaTriePolicy::getProperty(const char *const query, const int queryLength,
+        char *const outResult, const int maxResultLength) {
+    const int compareLength = queryLength + 1 /* terminator */;
+    if (strncmp(query, UNIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d",
+                mEntryCounters.getNgramCount(NgramType::Unigram));
+    } else if (strncmp(query, BIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d", mEntryCounters.getNgramCount(NgramType::Bigram));
+    } else if (strncmp(query, MAX_UNIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d",
+                mHeaderPolicy->isDecayingDict() ?
+                        ForgettingCurveUtils::getEntryCountHardLimit(
+                                mHeaderPolicy->getMaxNgramCounts().getNgramCount(
+                                        NgramType::Unigram)) :
+                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    } else if (strncmp(query, MAX_BIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d",
+                mHeaderPolicy->isDecayingDict() ?
+                        ForgettingCurveUtils::getEntryCountHardLimit(
+                                mHeaderPolicy->getMaxNgramCounts().getNgramCount(
+                                        NgramType::Bigram)) :
+                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    }
+}
+
+const WordProperty Ver4PatriciaTriePolicy::getWordProperty(
+        const CodePointArrayView wordCodePoints) const {
+    const int wordId = getWordId(wordCodePoints, false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) {
+        AKLOGE("getWordProperty is called for invalid word.");
+        return WordProperty();
+    }
+    const LanguageModelDictContent *const languageModelDictContent =
+            mBuffers->getLanguageModelDictContent();
+    // Fetch ngram information.
+    std::vector<NgramProperty> ngrams;
+    int ngramTargetCodePoints[MAX_WORD_LENGTH];
+    int ngramPrevWordsCodePoints[MAX_PREV_WORD_COUNT_FOR_N_GRAM][MAX_WORD_LENGTH];
+    int ngramPrevWordsCodePointCount[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    bool ngramPrevWordIsBeginningOfSentense[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    for (const auto entry : languageModelDictContent->exportAllNgramEntriesRelatedToWord(
+            mHeaderPolicy, wordId)) {
+        const int codePointCount = getCodePointsAndReturnCodePointCount(entry.getTargetWordId(),
+                MAX_WORD_LENGTH, ngramTargetCodePoints);
+        const WordIdArrayView prevWordIds = entry.getPrevWordIds();
+        for (size_t i = 0; i < prevWordIds.size(); ++i) {
+            ngramPrevWordsCodePointCount[i] = getCodePointsAndReturnCodePointCount(prevWordIds[i],
+                       MAX_WORD_LENGTH, ngramPrevWordsCodePoints[i]);
+            ngramPrevWordIsBeginningOfSentense[i] = languageModelDictContent->getProbabilityEntry(
+                    prevWordIds[i]).representsBeginningOfSentence();
+            if (ngramPrevWordIsBeginningOfSentense[i]) {
+                ngramPrevWordsCodePointCount[i] = CharUtils::removeBeginningOfSentenceMarker(
+                        ngramPrevWordsCodePoints[i], ngramPrevWordsCodePointCount[i]);
+            }
+        }
+        const NgramContext ngramContext(ngramPrevWordsCodePoints, ngramPrevWordsCodePointCount,
+                ngramPrevWordIsBeginningOfSentense, prevWordIds.size());
+        const ProbabilityEntry ngramProbabilityEntry = entry.getProbabilityEntry();
+        const HistoricalInfo *const historicalInfo = ngramProbabilityEntry.getHistoricalInfo();
+        // TODO: Output flags in WordAttributes.
+        ngrams.emplace_back(ngramContext,
+                CodePointArrayView(ngramTargetCodePoints, codePointCount).toVector(),
+                entry.getWordAttributes().getProbability(), *historicalInfo);
+    }
+    // Fetch shortcut information.
+    std::vector<UnigramProperty::ShortcutProperty> shortcuts;
+    int shortcutPos = getShortcutPositionOfWord(wordId);
+    if (shortcutPos != NOT_A_DICT_POS) {
+        int shortcutTarget[MAX_WORD_LENGTH];
+        const ShortcutDictContent *const shortcutDictContent =
+                mBuffers->getShortcutDictContent();
+        bool hasNext = true;
+        while (hasNext) {
+            int shortcutTargetLength = 0;
+            int shortcutProbability = NOT_A_PROBABILITY;
+            shortcutDictContent->getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH, shortcutTarget,
+                    &shortcutTargetLength, &shortcutProbability, &hasNext, &shortcutPos);
+            shortcuts.emplace_back(
+                    CodePointArrayView(shortcutTarget, shortcutTargetLength).toVector(),
+                    shortcutProbability);
+        }
+    }
+    const WordAttributes wordAttributes = languageModelDictContent->getWordAttributes(
+            WordIdArrayView(), wordId, true /* mustMatchAllPrevWords */, mHeaderPolicy);
+    const ProbabilityEntry probabilityEntry = languageModelDictContent->getProbabilityEntry(wordId);
+    const HistoricalInfo *const historicalInfo = probabilityEntry.getHistoricalInfo();
+    const UnigramProperty unigramProperty(probabilityEntry.representsBeginningOfSentence(),
+            wordAttributes.isNotAWord(), wordAttributes.isBlacklisted(),
+            wordAttributes.isPossiblyOffensive(), wordAttributes.getProbability(),
+            *historicalInfo, std::move(shortcuts));
+    return WordProperty(wordCodePoints.toVector(), unigramProperty, ngrams);
+}
+
+int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outCodePoints,
+        int *const outCodePointCount) {
+    *outCodePointCount = 0;
+    if (token == 0) {
+        mTerminalPtNodePositionsForIteratingWords.clear();
+        DynamicPtReadingHelper::TraversePolicyToGetAllTerminalPtNodePositions traversePolicy(
+                &mTerminalPtNodePositionsForIteratingWords);
+        DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+        readingHelper.initWithPtNodeArrayPos(getRootPosition());
+        readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(&traversePolicy);
+    }
+    const int terminalPtNodePositionsVectorSize =
+            static_cast<int>(mTerminalPtNodePositionsForIteratingWords.size());
+    if (token < 0 || token >= terminalPtNodePositionsVectorSize) {
+        AKLOGE("Given token %d is invalid.", token);
+        return 0;
+    }
+    const int terminalPtNodePos = mTerminalPtNodePositionsForIteratingWords[token];
+    const PtNodeParams ptNodeParams =
+            mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(terminalPtNodePos);
+    *outCodePointCount = getCodePointsAndReturnCodePointCount(ptNodeParams.getTerminalId(),
+            MAX_WORD_LENGTH, outCodePoints);
+    const int nextToken = token + 1;
+    if (nextToken >= terminalPtNodePositionsVectorSize) {
+        // All words have been iterated.
+        mTerminalPtNodePositionsForIteratingWords.clear();
+        return 0;
+    }
+    return nextToken;
+}
+
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_policy.h
index faad4290d..d130a4e78 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_policy.h
@@ -20,40 +20,38 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
-#include "suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
+#include "dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_writing_helper.h"
+#include "dictionary/structure/v4/ver4_pt_node_array_reader.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/entry_counters.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 class DicNode;
 class DicNodeVector;
 
+// Word id = Artificial id that is stored in the PtNode looked up by the word.
 class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
  public:
     Ver4PatriciaTriePolicy(Ver4DictBuffers::Ver4DictBuffersPtr buffers)
             : mBuffers(std::move(buffers)), mHeaderPolicy(mBuffers->getHeaderPolicy()),
               mDictBuffer(mBuffers->getWritableTrieBuffer()),
-              mBigramPolicy(mBuffers->getMutableBigramDictContent(),
-                      mBuffers->getTerminalPositionLookupTable(), mHeaderPolicy),
               mShortcutPolicy(mBuffers->getMutableShortcutDictContent(),
                       mBuffers->getTerminalPositionLookupTable()),
-              mNodeReader(mDictBuffer, mBuffers->getLanguageModelDictContent(), mHeaderPolicy),
-              mPtNodeArrayReader(mDictBuffer),
-              mNodeWriter(mDictBuffer, mBuffers.get(), mHeaderPolicy, &mNodeReader,
-                      &mPtNodeArrayReader, &mBigramPolicy, &mShortcutPolicy),
+              mNodeReader(mDictBuffer), mPtNodeArrayReader(mDictBuffer),
+              mNodeWriter(mDictBuffer, mBuffers.get(), &mNodeReader, &mPtNodeArrayReader,
+                      &mShortcutPolicy),
               mUpdatingHelper(mDictBuffer, &mNodeReader, &mNodeWriter),
               mWritingHelper(mBuffers.get()),
-              mUnigramCount(mHeaderPolicy->getUnigramCount()),
-              mBigramCount(mHeaderPolicy->getBigramCount()),
+              mEntryCounters(mHeaderPolicy->getNgramCounts().getCountArray()),
               mTerminalPtNodePositionsForIteratingWords(), mIsCorrupted(false) {};
 
     AK_FORCE_INLINE int getRootPosition() const {
@@ -63,40 +61,44 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     void createAndGetAllChildDicNodes(const DicNode *const dicNode,
             DicNodeVector *const childDicNodes) const;
 
-    int getCodePointsAndProbabilityAndReturnCodePointCount(
-            const int terminalPtNodePos, const int maxCodePointCount, int *const outCodePoints,
-            int *const outUnigramProbability) const;
+    int getCodePointsAndReturnCodePointCount(const int wordId, const int maxCodePointCount,
+            int *const outCodePoints) const;
 
-    int getTerminalPtNodePositionOfWord(const int *const inWord,
-            const int length, const bool forceLowerCaseSearch) const;
+    int getWordId(const CodePointArrayView wordCodePoints, const bool forceLowerCaseSearch) const;
 
-    int getProbability(const int unigramProbability, const int bigramProbability) const;
+    const WordAttributes getWordAttributesInContext(const WordIdArrayView prevWordIds,
+            const int wordId, MultiBigramMap *const multiBigramMap) const;
 
-    int getProbabilityOfPtNode(const int *const prevWordsPtNodePos, const int ptNodePos) const;
+    // TODO: Remove
+    int getProbability(const int unigramProbability, const int bigramProbability) const {
+        // Not used.
+        return NOT_A_PROBABILITY;
+    }
+
+    int getProbabilityOfWord(const WordIdArrayView prevWordIds, const int wordId) const;
 
-    void iterateNgramEntries(const int *const prevWordsPtNodePos,
+    void iterateNgramEntries(const WordIdArrayView prevWordIds,
             NgramListener *const listener) const;
 
-    int getShortcutPositionOfPtNode(const int ptNodePos) const;
+    BinaryDictionaryShortcutIterator getShortcutIterator(const int wordId) const;
 
     const DictionaryHeaderStructurePolicy *getHeaderStructurePolicy() const {
         return mHeaderPolicy;
     }
 
-    const DictionaryShortcutsStructurePolicy *getShortcutsStructurePolicy() const {
-        return &mShortcutPolicy;
-    }
-
-    bool addUnigramEntry(const int *const word, const int length,
+    bool addUnigramEntry(const CodePointArrayView wordCodePoints,
             const UnigramProperty *const unigramProperty);
 
-    bool removeUnigramEntry(const int *const word, const int length);
+    bool removeUnigramEntry(const CodePointArrayView wordCodePoints);
+
+    bool addNgramEntry(const NgramProperty *const ngramProperty);
 
-    bool addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const BigramProperty *const bigramProperty);
+    bool removeNgramEntry(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints);
 
-    bool removeNgramEntry(const PrevWordsInfo *const prevWordsInfo, const int *const word1,
-            const int length1);
+    bool updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+            const CodePointArrayView wordCodePoints, const bool isValidWord,
+            const HistoricalInfo historicalInfo);
 
     bool flush(const char *const filePath);
 
@@ -107,8 +109,7 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     void getProperty(const char *const query, const int queryLength, char *const outResult,
             const int maxResultLength);
 
-    const WordProperty getWordProperty(const int *const codePoints,
-            const int codePointCount) const;
+    const WordProperty getWordProperty(const CodePointArrayView wordCodePoints) const;
 
     int getNextWordAndNextToken(const int token, int *const outCodePoints,
             int *const outCodePointCount);
@@ -132,19 +133,17 @@ class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
     const Ver4DictBuffers::Ver4DictBuffersPtr mBuffers;
     const HeaderPolicy *const mHeaderPolicy;
     BufferWithExtendableBuffer *const mDictBuffer;
-    Ver4BigramListPolicy mBigramPolicy;
     Ver4ShortcutListPolicy mShortcutPolicy;
     Ver4PatriciaTrieNodeReader mNodeReader;
     Ver4PtNodeArrayReader mPtNodeArrayReader;
     Ver4PatriciaTrieNodeWriter mNodeWriter;
     DynamicPtUpdatingHelper mUpdatingHelper;
     Ver4PatriciaTrieWritingHelper mWritingHelper;
-    int mUnigramCount;
-    int mBigramCount;
+    MutableEntryCounters mEntryCounters;
     std::vector<int> mTerminalPtNodePositionsForIteratingWords;
     mutable bool mIsCorrupted;
 
-    int getBigramsPositionOfPtNode(const int ptNodePos) const;
+    int getShortcutPositionOfWord(const int wordId) const;
 };
 } // namespace latinime
 #endif // LATINIME_VER4_PATRICIA_TRIE_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
index 254022db4..ccb70cdd3 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
index 466ff55d5..466ff55d5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
diff --git a/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
new file mode 100644
index 000000000..6dfdf4d31
--- /dev/null
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
@@ -0,0 +1,185 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/structure/v4/ver4_patricia_trie_writing_helper.h"
+
+#include <cstring>
+#include <queue>
+
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/structure/v4/ver4_dict_constants.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
+#include "dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
+#include "dictionary/structure/v4/ver4_pt_node_array_reader.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/file_utils.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
+#include "utils/ngram_utils.h"
+
+namespace latinime {
+
+bool Ver4PatriciaTrieWritingHelper::writeToDictFile(const char *const dictDirPath,
+        const EntryCounts &entryCounts) const {
+    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
+    BufferWithExtendableBuffer headerBuffer(
+            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+    const int extendedRegionSize = headerPolicy->getExtendedRegionSize()
+            + mBuffers->getTrieBuffer()->getUsedAdditionalBufferSize();
+    if (!headerPolicy->fillInAndWriteHeaderToBuffer(false /* updatesLastDecayedTime */,
+            entryCounts, extendedRegionSize, &headerBuffer)) {
+        AKLOGE("Cannot write header structure to buffer. "
+                "updatesLastDecayedTime: %d, unigramCount: %d, bigramCount: %d, trigramCount: %d,"
+                "extendedRegionSize: %d", false, entryCounts.getNgramCount(NgramType::Unigram),
+                entryCounts.getNgramCount(NgramType::Bigram),
+                entryCounts.getNgramCount(NgramType::Trigram),
+                extendedRegionSize);
+        return false;
+    }
+    return mBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
+}
+
+bool Ver4PatriciaTrieWritingHelper::writeToDictFileWithGC(const int rootPtNodeArrayPos,
+        const char *const dictDirPath) {
+    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
+    Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers(
+            Ver4DictBuffers::createVer4DictBuffers(headerPolicy,
+                    Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    MutableEntryCounters entryCounters;
+    if (!runGC(rootPtNodeArrayPos, headerPolicy, dictBuffers.get(), &entryCounters)) {
+        return false;
+    }
+    BufferWithExtendableBuffer headerBuffer(
+            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+    if (!headerPolicy->fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
+            entryCounters.getEntryCounts(), 0 /* extendedRegionSize */, &headerBuffer)) {
+        return false;
+    }
+    return dictBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
+}
+
+bool Ver4PatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
+        const HeaderPolicy *const headerPolicy, Ver4DictBuffers *const buffersToWrite,
+        MutableEntryCounters *const outEntryCounters) {
+    Ver4PatriciaTrieNodeReader ptNodeReader(mBuffers->getTrieBuffer());
+    Ver4PtNodeArrayReader ptNodeArrayReader(mBuffers->getTrieBuffer());
+    Ver4ShortcutListPolicy shortcutPolicy(mBuffers->getMutableShortcutDictContent(),
+            mBuffers->getTerminalPositionLookupTable());
+    Ver4PatriciaTrieNodeWriter ptNodeWriter(mBuffers->getWritableTrieBuffer(),
+            mBuffers, &ptNodeReader, &ptNodeArrayReader, &shortcutPolicy);
+
+    if (!mBuffers->getMutableLanguageModelDictContent()->updateAllProbabilityEntriesForGC(
+            headerPolicy, outEntryCounters)) {
+        AKLOGE("Failed to update probabilities in language model dict content.");
+        return false;
+    }
+    if (headerPolicy->isDecayingDict()) {
+        const EntryCounts &maxEntryCounts = headerPolicy->getMaxNgramCounts();
+        if (!mBuffers->getMutableLanguageModelDictContent()->truncateEntries(
+                outEntryCounters->getEntryCounts(), maxEntryCounts, headerPolicy,
+                outEntryCounters)) {
+            AKLOGE("Failed to truncate entries in language model dict content.");
+            return false;
+        }
+    }
+
+    DynamicPtReadingHelper readingHelper(&ptNodeReader, &ptNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    DynamicPtGcEventListeners
+            ::TraversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
+                    traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted(
+                            &ptNodeWriter);
+    if (!readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
+            &traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted)) {
+        return false;
+    }
+
+    // Mapping from positions in mBuffer to positions in bufferToWrite.
+    PtNodeWriter::DictPositionRelocationMap dictPositionRelocationMap;
+    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    Ver4PatriciaTrieNodeWriter ptNodeWriterForNewBuffers(buffersToWrite->getWritableTrieBuffer(),
+            buffersToWrite, &ptNodeReader, &ptNodeArrayReader, &shortcutPolicy);
+    DynamicPtGcEventListeners::TraversePolicyToPlaceAndWriteValidPtNodesToBuffer
+            traversePolicyToPlaceAndWriteValidPtNodesToBuffer(&ptNodeWriterForNewBuffers,
+                    buffersToWrite->getWritableTrieBuffer(), &dictPositionRelocationMap);
+    if (!readingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
+            &traversePolicyToPlaceAndWriteValidPtNodesToBuffer)) {
+        return false;
+    }
+
+    // Create policy instances for the GCed dictionary.
+    Ver4PatriciaTrieNodeReader newPtNodeReader(buffersToWrite->getTrieBuffer());
+    Ver4PtNodeArrayReader newPtNodeArrayreader(buffersToWrite->getTrieBuffer());
+    Ver4ShortcutListPolicy newShortcutPolicy(buffersToWrite->getMutableShortcutDictContent(),
+            buffersToWrite->getTerminalPositionLookupTable());
+    Ver4PatriciaTrieNodeWriter newPtNodeWriter(buffersToWrite->getWritableTrieBuffer(),
+            buffersToWrite, &newPtNodeReader, &newPtNodeArrayreader,
+            &newShortcutPolicy);
+    // Re-assign terminal IDs for valid terminal PtNodes.
+    TerminalPositionLookupTable::TerminalIdMap terminalIdMap;
+    if(!buffersToWrite->getMutableTerminalPositionLookupTable()->runGCTerminalIds(
+            &terminalIdMap)) {
+        return false;
+    }
+    // Run GC for language model dict content.
+    if (!buffersToWrite->getMutableLanguageModelDictContent()->runGC(&terminalIdMap,
+            mBuffers->getLanguageModelDictContent())) {
+        return false;
+    }
+    // Run GC for shortcut dict content.
+    if(!buffersToWrite->getMutableShortcutDictContent()->runGC(&terminalIdMap,
+            mBuffers->getShortcutDictContent())) {
+        return false;
+    }
+    DynamicPtReadingHelper newDictReadingHelper(&newPtNodeReader, &newPtNodeArrayreader);
+    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    DynamicPtGcEventListeners::TraversePolicyToUpdateAllPositionFields
+            traversePolicyToUpdateAllPositionFields(&newPtNodeWriter, &dictPositionRelocationMap);
+    if (!newDictReadingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
+            &traversePolicyToUpdateAllPositionFields)) {
+        return false;
+    }
+    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
+            traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds(&newPtNodeWriter, &terminalIdMap);
+    if (!newDictReadingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
+            &traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds)) {
+        return false;
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieWritingHelper::TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
+        ::onVisitingPtNode(const PtNodeParams *const ptNodeParams) {
+    if (!ptNodeParams->isTerminal()) {
+        return true;
+    }
+    TerminalPositionLookupTable::TerminalIdMap::const_iterator it =
+            mTerminalIdMap->find(ptNodeParams->getTerminalId());
+    if (it == mTerminalIdMap->end()) {
+        AKLOGE("terminal Id %d is not in the terminal position map. map size: %zd",
+                ptNodeParams->getTerminalId(), mTerminalIdMap->size());
+        return false;
+    }
+    if (!mPtNodeWriter->updateTerminalId(ptNodeParams, it->second)) {
+        AKLOGE("Cannot update terminal id. %d -> %d", it->first, it->second);
+        return false;
+    }
+    return true;
+}
+
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
index bb464ad28..68dd1caa2 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
@@ -18,8 +18,9 @@
 #define LATINIME_VER4_PATRICIA_TRIE_WRITING_HELPER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
+#include "dictionary/structure/v4/content/terminal_position_lookup_table.h"
+#include "dictionary/utils/entry_counters.h"
 
 namespace latinime {
 
@@ -33,8 +34,7 @@ class Ver4PatriciaTrieWritingHelper {
     Ver4PatriciaTrieWritingHelper(Ver4DictBuffers *const buffers)
             : mBuffers(buffers) {}
 
-    bool writeToDictFile(const char *const dictDirPath, const int unigramCount,
-            const int bigramCount) const;
+    bool writeToDictFile(const char *const dictDirPath, const EntryCounts &entryCounts) const;
 
     // This method cannot be const because the original dictionary buffer will be updated to detect
     // useless PtNodes during GC.
@@ -66,57 +66,8 @@ class Ver4PatriciaTrieWritingHelper {
         const TerminalPositionLookupTable::TerminalIdMap *const mTerminalIdMap;
     };
 
-    // For truncateUnigrams() and truncateBigrams().
-    class DictProbability {
-     public:
-        DictProbability(const int dictPos, const int probability, const int timestamp)
-                : mDictPos(dictPos), mProbability(probability), mTimestamp(timestamp) {}
-
-        int getDictPos() const {
-            return mDictPos;
-        }
-
-        int getProbability() const {
-            return mProbability;
-        }
-
-        int getTimestamp() const {
-            return mTimestamp;
-        }
-
-     private:
-        DISALLOW_DEFAULT_CONSTRUCTOR(DictProbability);
-
-        int mDictPos;
-        int mProbability;
-        int mTimestamp;
-    };
-
-    // For truncateUnigrams() and truncateBigrams().
-    class DictProbabilityComparator {
-     public:
-        bool operator()(const DictProbability &left, const DictProbability &right) {
-            if (left.getProbability() != right.getProbability()) {
-                return left.getProbability() > right.getProbability();
-            }
-            if (left.getTimestamp() != right.getTimestamp()) {
-                return left.getTimestamp() < right.getTimestamp();
-            }
-            return left.getDictPos() > right.getDictPos();
-        }
-
-     private:
-        DISALLOW_ASSIGNMENT_OPERATOR(DictProbabilityComparator);
-    };
-
     bool runGC(const int rootPtNodeArrayPos, const HeaderPolicy *const headerPolicy,
-            Ver4DictBuffers *const buffersToWrite, int *const outUnigramCount,
-            int *const outBigramCount);
-
-    bool truncateUnigrams(const Ver4PatriciaTrieNodeReader *const ptNodeReader,
-            Ver4PatriciaTrieNodeWriter *const ptNodeWriter, const int maxUnigramCount);
-
-    bool truncateBigrams(const int maxBigramCount);
+            Ver4DictBuffers *const buffersToWrite, MutableEntryCounters *const outEntryCounters);
 
     Ver4DictBuffers *const mBuffers;
 };
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.cpp b/native/jni/src/dictionary/structure/v4/ver4_pt_node_array_reader.cpp
index b014c523d..63d0b4ad5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.cpp
+++ b/native/jni/src/dictionary/structure/v4/ver4_pt_node_array_reader.cpp
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h"
+#include "dictionary/structure/v4/ver4_pt_node_array_reader.h"
 
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h b/native/jni/src/dictionary/structure/v4/ver4_pt_node_array_reader.h
index d81808efc..ccb760bc1 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h
+++ b/native/jni/src/dictionary/structure/v4/ver4_pt_node_array_reader.h
@@ -18,7 +18,7 @@
 #define LATINIME_VER4_PT_NODE_ARRAY_READER_H
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h"
+#include "dictionary/structure/pt_common/pt_node_array_reader.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/core/dictionary/binary_dictionary_bigrams_iterator.h b/native/jni/src/dictionary/utils/binary_dictionary_bigrams_iterator.h
index 178b06554..8a614730b 100644
--- a/native/jni/src/suggest/core/dictionary/binary_dictionary_bigrams_iterator.h
+++ b/native/jni/src/dictionary/utils/binary_dictionary_bigrams_iterator.h
@@ -18,7 +18,7 @@
 #define LATINIME_BINARY_DICTIONARY_BIGRAMS_ITERATOR_H
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
+#include "dictionary/interface/dictionary_bigrams_structure_policy.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/core/dictionary/binary_dictionary_shortcut_iterator.h b/native/jni/src/dictionary/utils/binary_dictionary_shortcut_iterator.h
index 558e0a5c3..a4ddd58c2 100644
--- a/native/jni/src/suggest/core/dictionary/binary_dictionary_shortcut_iterator.h
+++ b/native/jni/src/dictionary/utils/binary_dictionary_shortcut_iterator.h
@@ -18,7 +18,7 @@
 #define LATINIME_BINARY_DICTIONARY_SHORTCUT_ITERATOR_H
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
+#include "dictionary/interface/dictionary_shortcuts_structure_policy.h"
 
 namespace latinime {
 
@@ -31,6 +31,11 @@ class BinaryDictionaryShortcutIterator {
               mPos(shortcutStructurePolicy->getStartPos(shortcutPos)),
               mHasNextShortcutTarget(shortcutPos != NOT_A_DICT_POS) {}
 
+    BinaryDictionaryShortcutIterator(const BinaryDictionaryShortcutIterator &&shortcutIterator)
+            : mShortcutStructurePolicy(shortcutIterator.mShortcutStructurePolicy),
+              mPos(shortcutIterator.mPos),
+              mHasNextShortcutTarget(shortcutIterator.mHasNextShortcutTarget) {}
+
     AK_FORCE_INLINE bool hasNextShortcutTarget() const {
         return mHasNextShortcutTarget;
     }
@@ -45,7 +50,8 @@ class BinaryDictionaryShortcutIterator {
     }
 
  private:
-    DISALLOW_IMPLICIT_CONSTRUCTORS(BinaryDictionaryShortcutIterator);
+    DISALLOW_DEFAULT_CONSTRUCTOR(BinaryDictionaryShortcutIterator);
+    DISALLOW_ASSIGNMENT_OPERATOR(BinaryDictionaryShortcutIterator);
 
     const DictionaryShortcutsStructurePolicy *const mShortcutStructurePolicy;
     int mPos;
diff --git a/native/jni/src/suggest/core/dictionary/bloom_filter.h b/native/jni/src/dictionary/utils/bloom_filter.h
index 1e60f49ed..1e60f49ed 100644
--- a/native/jni/src/suggest/core/dictionary/bloom_filter.h
+++ b/native/jni/src/dictionary/utils/bloom_filter.h
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp b/native/jni/src/dictionary/utils/buffer_with_extendable_buffer.cpp
index 833063c17..217569651 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.cpp
+++ b/native/jni/src/dictionary/utils/buffer_with_extendable_buffer.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
@@ -31,7 +31,7 @@ uint32_t BufferWithExtendableBuffer::readUint(const int size, const int pos) con
 
 uint32_t BufferWithExtendableBuffer::readUintAndAdvancePosition(const int size,
         int *const pos) const {
-    const int value = readUint(size, *pos);
+    const uint32_t value = readUint(size, *pos);
     *pos += size;
     return value;
 }
@@ -42,8 +42,10 @@ void BufferWithExtendableBuffer::readCodePointsAndAdvancePosition(const int maxC
     if (readingPosIsInAdditionalBuffer) {
         *pos -= mOriginalBuffer.size();
     }
+    // Code point table is not used for dynamic format.
     *outCodePointCount = ByteArrayUtils::readStringAndAdvancePosition(
-            getBuffer(readingPosIsInAdditionalBuffer), maxCodePointCount, outCodePoints, pos);
+            getBuffer(readingPosIsInAdditionalBuffer), maxCodePointCount,
+            nullptr /* codePointTable */, outCodePoints, pos);
     if (readingPosIsInAdditionalBuffer) {
         *pos += mOriginalBuffer.size();
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h b/native/jni/src/dictionary/utils/buffer_with_extendable_buffer.h
index fad83aa25..0a141d4db 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h
+++ b/native/jni/src/dictionary/utils/buffer_with_extendable_buffer.h
@@ -22,7 +22,7 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.cpp b/native/jni/src/dictionary/utils/byte_array_utils.cpp
index 1833e8832..d38f08217 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.cpp
+++ b/native/jni/src/dictionary/utils/byte_array_utils.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h b/native/jni/src/dictionary/utils/byte_array_utils.h
index c0a9fcb1d..abb979050 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/byte_array_utils.h
+++ b/native/jni/src/dictionary/utils/byte_array_utils.h
@@ -114,7 +114,7 @@ class ByteArrayUtils {
         return buffer[(*pos)++];
     }
 
-    static AK_FORCE_INLINE int readUint(const uint8_t *const buffer,
+    static AK_FORCE_INLINE uint32_t readUint(const uint8_t *const buffer,
             const int size, const int pos) {
         // size must be in 1 to 4.
         ASSERT(size >= 1 && size <= 4);
@@ -147,11 +147,18 @@ class ByteArrayUtils {
      */
     static AK_FORCE_INLINE int readCodePoint(const uint8_t *const buffer, const int pos) {
         int p = pos;
-        return readCodePointAndAdvancePosition(buffer, &p);
+        return readCodePointAndAdvancePosition(buffer, nullptr /* codePointTable */, &p);
     }
 
     static AK_FORCE_INLINE int readCodePointAndAdvancePosition(
-            const uint8_t *const buffer, int *const pos) {
+            const uint8_t *const buffer, const int *const codePointTable, int *const pos) {
+        /*
+         * codePointTable is an array to convert the most frequent characters in this dictionary to
+         * 1 byte code points. It is only made of the original code points of the most frequent
+         * characters used in this dictionary. 0x20 - 0xFF is used for the 1 byte characters.
+         * The original code points are restored by picking the code points at the indices of the
+         * codePointTable. The indices are calculated by subtracting 0x20 from the firstByte.
+         */
         const uint8_t firstByte = readUint8(buffer, *pos);
         if (firstByte < MINIMUM_ONE_BYTE_CHARACTER_VALUE) {
             if (firstByte == CHARACTER_ARRAY_TERMINATOR) {
@@ -162,6 +169,9 @@ class ByteArrayUtils {
             }
         } else {
             *pos += 1;
+            if (codePointTable) {
+                return codePointTable[firstByte - MINIMUM_ONE_BYTE_CHARACTER_VALUE];
+            }
             return firstByte;
         }
     }
@@ -173,12 +183,13 @@ class ByteArrayUtils {
      */
     // Returns the length of the string.
     static int readStringAndAdvancePosition(const uint8_t *const buffer,
-            const int maxLength, int *const outBuffer, int *const pos) {
+            const int maxLength, const int *const codePointTable, int *const outBuffer,
+            int *const pos) {
         int length = 0;
-        int codePoint = readCodePointAndAdvancePosition(buffer, pos);
+        int codePoint = readCodePointAndAdvancePosition(buffer, codePointTable, pos);
         while (NOT_A_CODE_POINT != codePoint && length < maxLength) {
             outBuffer[length++] = codePoint;
-            codePoint = readCodePointAndAdvancePosition(buffer, pos);
+            codePoint = readCodePointAndAdvancePosition(buffer, codePointTable, pos);
         }
         return length;
     }
@@ -187,9 +198,9 @@ class ByteArrayUtils {
     static int advancePositionToBehindString(
             const uint8_t *const buffer, const int maxLength, int *const pos) {
         int length = 0;
-        int codePoint = readCodePointAndAdvancePosition(buffer, pos);
+        int codePoint = readCodePointAndAdvancePosition(buffer, nullptr /* codePointTable */, pos);
         while (NOT_A_CODE_POINT != codePoint && length < maxLength) {
-            codePoint = readCodePointAndAdvancePosition(buffer, pos);
+            codePoint = readCodePointAndAdvancePosition(buffer, nullptr /* codePointTable */, pos);
             length++;
         }
         return length;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp b/native/jni/src/dictionary/utils/dict_file_writing_utils.cpp
index b7e2a7278..033a758ba 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
+++ b/native/jni/src/dictionary/utils/dict_file_writing_utils.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
 
 #include <cstdio>
 #include <errno.h>
@@ -22,13 +22,14 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/backward/v402/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/structure/backward/v402/ver4_dict_buffers.h"
+#include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "dictionary/structure/v4/ver4_dict_buffers.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/entry_counters.h"
+#include "dictionary/utils/file_utils.h"
+#include "dictionary/utils/format_utils.h"
 #include "utils/time_keeper.h"
 
 namespace latinime {
@@ -43,13 +44,13 @@ const int DictFileWritingUtils::SIZE_OF_BUFFER_SIZE_FIELD = 4;
     TimeKeeper::setCurrentTime();
     const FormatUtils::FORMAT_VERSION formatVersion = FormatUtils::getFormatVersion(dictVersion);
     switch (formatVersion) {
-        case FormatUtils::VERSION_4:
+        case FormatUtils::VERSION_402:
             return createEmptyV4DictFile<backward::v402::Ver4DictConstants,
                     backward::v402::Ver4DictBuffers,
                     backward::v402::Ver4DictBuffers::Ver4DictBuffersPtr>(
                             filePath, localeAsCodePointVector, attributeMap, formatVersion);
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
-        case FormatUtils::VERSION_4_DEV:
+        case FormatUtils::VERSION_403:
             return createEmptyV4DictFile<Ver4DictConstants, Ver4DictBuffers,
                     Ver4DictBuffers::Ver4DictBuffersPtr>(
                             filePath, localeAsCodePointVector, attributeMap, formatVersion);
@@ -69,8 +70,7 @@ template<class DictConstants, class DictBuffers, class DictBuffersPtr>
     DictBuffersPtr dictBuffers = DictBuffers::createVer4DictBuffers(&headerPolicy,
             DictConstants::MAX_DICT_EXTENDED_REGION_SIZE);
     headerPolicy.fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
-            0 /* unigramCount */, 0 /* bigramCount */,
-            0 /* extendedRegionSize */, dictBuffers->getWritableHeaderBuffer());
+            EntryCounts(), 0 /* extendedRegionSize */, dictBuffers->getWritableHeaderBuffer());
     if (!DynamicPtWritingUtils::writeEmptyDictionary(
             dictBuffers->getWritableTrieBuffer(), 0 /* rootPos */)) {
         AKLOGE("Empty ver4 dictionary structure cannot be created on memory.");
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h b/native/jni/src/dictionary/utils/dict_file_writing_utils.h
index 4843b3b32..102a89da4 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
+++ b/native/jni/src/dictionary/utils/dict_file_writing_utils.h
@@ -20,8 +20,8 @@
 #include <cstdio>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/header/header_read_write_utils.h"
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "dictionary/header/header_read_write_utils.h"
+#include "dictionary/utils/format_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/dictionary/utils/entry_counters.h b/native/jni/src/dictionary/utils/entry_counters.h
new file mode 100644
index 000000000..5e443026e
--- /dev/null
+++ b/native/jni/src/dictionary/utils/entry_counters.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_ENTRY_COUNTERS_H
+#define LATINIME_ENTRY_COUNTERS_H
+
+#include <array>
+
+#include "defines.h"
+#include "utils/ngram_utils.h"
+
+namespace latinime {
+
+// Copyable but immutable
+class EntryCounts final {
+ public:
+    EntryCounts() : mEntryCounts({{0, 0, 0, 0}}) {}
+
+    explicit EntryCounts(const std::array<int, MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1> &counters)
+            : mEntryCounts(counters) {}
+
+    int getNgramCount(const NgramType ngramType) const {
+        return mEntryCounts[static_cast<int>(ngramType)];
+    }
+
+    const std::array<int, MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1> &getCountArray() const {
+        return mEntryCounts;
+    }
+
+ private:
+    DISALLOW_ASSIGNMENT_OPERATOR(EntryCounts);
+
+    // Counts from Unigram (0-th element) to (MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1)-gram
+    // (MAX_PREV_WORD_COUNT_FOR_N_GRAM-th element)
+    const std::array<int, MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1> mEntryCounts;
+};
+
+class MutableEntryCounters final {
+ public:
+    MutableEntryCounters() {
+        mEntryCounters.fill(0);
+    }
+
+    explicit MutableEntryCounters(
+            const std::array<int, MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1> &counters)
+            : mEntryCounters(counters) {}
+
+    const EntryCounts getEntryCounts() const {
+        return EntryCounts(mEntryCounters);
+    }
+
+    void incrementNgramCount(const NgramType ngramType) {
+        ++mEntryCounters[static_cast<int>(ngramType)];
+    }
+
+    void decrementNgramCount(const NgramType ngramType) {
+        --mEntryCounters[static_cast<int>(ngramType)];
+    }
+
+    int getNgramCount(const NgramType ngramType) const {
+        return mEntryCounters[static_cast<int>(ngramType)];
+    }
+
+    void setNgramCount(const NgramType ngramType, const int count) {
+        mEntryCounters[static_cast<int>(ngramType)] = count;
+    }
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(MutableEntryCounters);
+
+    // Counters from Unigram (0-th element) to (MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1)-gram
+    // (MAX_PREV_WORD_COUNT_FOR_N_GRAM-th element)
+    std::array<int, MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1> mEntryCounters;
+};
+} // namespace latinime
+#endif /* LATINIME_ENTRY_COUNTERS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/file_utils.cpp b/native/jni/src/dictionary/utils/file_utils.cpp
index fb80f38c5..bb392fb32 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/file_utils.cpp
+++ b/native/jni/src/dictionary/utils/file_utils.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+#include "dictionary/utils/file_utils.h"
 
 #include <cstdio>
 #include <cstring>
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/file_utils.h b/native/jni/src/dictionary/utils/file_utils.h
index 4f1b93a6a..4f1b93a6a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/file_utils.h
+++ b/native/jni/src/dictionary/utils/file_utils.h
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp b/native/jni/src/dictionary/utils/forgetting_curve_utils.cpp
index fed0ae77e..d79ed911b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.cpp
+++ b/native/jni/src/dictionary/utils/forgetting_curve_utils.cpp
@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "dictionary/utils/forgetting_curve_utils.h"
 
 #include <algorithm>
 #include <cmath>
 #include <stdlib.h>
 
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/utils/probability_utils.h"
+#include "dictionary/header/header_policy.h"
+#include "dictionary/utils/probability_utils.h"
 #include "utils/time_keeper.h"
 
 namespace latinime {
@@ -29,13 +29,16 @@ namespace latinime {
 const int ForgettingCurveUtils::MULTIPLIER_TWO_IN_PROBABILITY_SCALE = 8;
 const int ForgettingCurveUtils::DECAY_INTERVAL_SECONDS = 2 * 60 * 60;
 
-const int ForgettingCurveUtils::MAX_LEVEL = 3;
-const int ForgettingCurveUtils::MIN_VISIBLE_LEVEL = 1;
-const int ForgettingCurveUtils::MAX_ELAPSED_TIME_STEP_COUNT = 15;
-const int ForgettingCurveUtils::DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD = 14;
+const int ForgettingCurveUtils::MAX_LEVEL = 15;
+const int ForgettingCurveUtils::MIN_VISIBLE_LEVEL = 2;
+const int ForgettingCurveUtils::MAX_ELAPSED_TIME_STEP_COUNT = 31;
+const int ForgettingCurveUtils::DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD = 30;
+const int ForgettingCurveUtils::OCCURRENCES_TO_RAISE_THE_LEVEL = 1;
+// TODO: Evaluate whether this should be 7.5 days.
+// 15 days
+const int ForgettingCurveUtils::DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS = 15 * 24 * 60 * 60;
 
-const float ForgettingCurveUtils::UNIGRAM_COUNT_HARD_LIMIT_WEIGHT = 1.2;
-const float ForgettingCurveUtils::BIGRAM_COUNT_HARD_LIMIT_WEIGHT = 1.2;
+const float ForgettingCurveUtils::ENTRY_COUNT_HARD_LIMIT_WEIGHT = 1.2;
 
 const ForgettingCurveUtils::ProbabilityTable ForgettingCurveUtils::sProbabilityTable;
 
@@ -43,7 +46,7 @@ const ForgettingCurveUtils::ProbabilityTable ForgettingCurveUtils::sProbabilityT
 /* static */ const HistoricalInfo ForgettingCurveUtils::createUpdatedHistoricalInfo(
         const HistoricalInfo *const originalHistoricalInfo, const int newProbability,
         const HistoricalInfo *const newHistoricalInfo, const HeaderPolicy *const headerPolicy) {
-    const int timestamp = newHistoricalInfo->getTimeStamp();
+    const int timestamp = newHistoricalInfo->getTimestamp();
     if (newProbability != NOT_A_PROBABILITY && originalHistoricalInfo->getLevel() == 0) {
         // Add entry as a valid word.
         const int level = clampToVisibleEntryLevelRange(newHistoricalInfo->getLevel());
@@ -54,19 +57,23 @@ const ForgettingCurveUtils::ProbabilityTable ForgettingCurveUtils::sProbabilityT
             || (originalHistoricalInfo->getLevel() == newHistoricalInfo->getLevel()
                     && originalHistoricalInfo->getCount() < newHistoricalInfo->getCount())) {
         // Initial information.
+        int count = newHistoricalInfo->getCount();
+        if (count >= OCCURRENCES_TO_RAISE_THE_LEVEL) {
+            const int level = clampToValidLevelRange(newHistoricalInfo->getLevel() + 1);
+            return HistoricalInfo(timestamp, level, 0 /* count */);
+        }
         const int level = clampToValidLevelRange(newHistoricalInfo->getLevel());
-        const int count = clampToValidCountRange(newHistoricalInfo->getCount(), headerPolicy);
-        return HistoricalInfo(timestamp, level, count);
+        return HistoricalInfo(timestamp, level, clampToValidCountRange(count, headerPolicy));
     } else {
         const int updatedCount = originalHistoricalInfo->getCount() + 1;
-        if (updatedCount >= headerPolicy->getForgettingCurveOccurrencesToLevelUp()) {
+        if (updatedCount >= OCCURRENCES_TO_RAISE_THE_LEVEL) {
             // The count exceeds the max value the level can be incremented.
             if (originalHistoricalInfo->getLevel() >= MAX_LEVEL) {
                 // The level is already max.
                 return HistoricalInfo(timestamp,
                         originalHistoricalInfo->getLevel(), originalHistoricalInfo->getCount());
             } else {
-                // Level up.
+                // Raise the level.
                 return HistoricalInfo(timestamp,
                         originalHistoricalInfo->getLevel() + 1, 0 /* count */);
             }
@@ -78,66 +85,54 @@ const ForgettingCurveUtils::ProbabilityTable ForgettingCurveUtils::sProbabilityT
 
 /* static */ int ForgettingCurveUtils::decodeProbability(
         const HistoricalInfo *const historicalInfo, const HeaderPolicy *const headerPolicy) {
-    const int elapsedTimeStepCount = getElapsedTimeStepCount(historicalInfo->getTimeStamp(),
-            headerPolicy->getForgettingCurveDurationToLevelDown());
+    const int elapsedTimeStepCount = getElapsedTimeStepCount(historicalInfo->getTimestamp(),
+            DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS);
     return sProbabilityTable.getProbability(
             headerPolicy->getForgettingCurveProbabilityValuesTableId(),
             clampToValidLevelRange(historicalInfo->getLevel()),
             clampToValidTimeStepCountRange(elapsedTimeStepCount));
 }
 
-/* static */ int ForgettingCurveUtils::getProbability(const int unigramProbability,
-        const int bigramProbability) {
-    if (unigramProbability == NOT_A_PROBABILITY) {
-        return NOT_A_PROBABILITY;
-    } else if (bigramProbability == NOT_A_PROBABILITY) {
-        return std::min(backoff(unigramProbability), MAX_PROBABILITY);
-    } else {
-        // TODO: Investigate better way to handle bigram probability.
-        return std::min(std::max(unigramProbability,
-                bigramProbability + MULTIPLIER_TWO_IN_PROBABILITY_SCALE), MAX_PROBABILITY);
-    }
-}
-
 /* static */ bool ForgettingCurveUtils::needsToKeep(const HistoricalInfo *const historicalInfo,
         const HeaderPolicy *const headerPolicy) {
     return historicalInfo->getLevel() > 0
-            || getElapsedTimeStepCount(historicalInfo->getTimeStamp(),
-                    headerPolicy->getForgettingCurveDurationToLevelDown())
+            || getElapsedTimeStepCount(historicalInfo->getTimestamp(),
+                    DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS)
                             < DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD;
 }
 
 /* static */ const HistoricalInfo ForgettingCurveUtils::createHistoricalInfoToSave(
         const HistoricalInfo *const originalHistoricalInfo,
         const HeaderPolicy *const headerPolicy) {
-    if (originalHistoricalInfo->getTimeStamp() == NOT_A_TIMESTAMP) {
+    if (originalHistoricalInfo->getTimestamp() == NOT_A_TIMESTAMP) {
         return HistoricalInfo();
     }
-    const int durationToLevelDownInSeconds = headerPolicy->getForgettingCurveDurationToLevelDown();
+    const int durationToLevelDownInSeconds = DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS;
     const int elapsedTimeStep = getElapsedTimeStepCount(
-            originalHistoricalInfo->getTimeStamp(), durationToLevelDownInSeconds);
+            originalHistoricalInfo->getTimestamp(), durationToLevelDownInSeconds);
     if (elapsedTimeStep <= MAX_ELAPSED_TIME_STEP_COUNT) {
         // No need to update historical info.
         return *originalHistoricalInfo;
     }
-    // Level down.
+    // Lower the level.
     const int maxLevelDownAmonut = elapsedTimeStep / (MAX_ELAPSED_TIME_STEP_COUNT + 1);
     const int levelDownAmount = (maxLevelDownAmonut >= originalHistoricalInfo->getLevel()) ?
             originalHistoricalInfo->getLevel() : maxLevelDownAmonut;
-    const int adjustedTimestampInSeconds = originalHistoricalInfo->getTimeStamp() +
+    const int adjustedTimestampInSeconds = originalHistoricalInfo->getTimestamp() +
             levelDownAmount * durationToLevelDownInSeconds;
     return HistoricalInfo(adjustedTimestampInSeconds,
             originalHistoricalInfo->getLevel() - levelDownAmount, 0 /* count */);
 }
 
 /* static */ bool ForgettingCurveUtils::needsToDecay(const bool mindsBlockByDecay,
-        const int unigramCount, const int bigramCount, const HeaderPolicy *const headerPolicy) {
-    if (unigramCount >= getUnigramCountHardLimit(headerPolicy->getMaxUnigramCount())) {
-        // Unigram count exceeds the limit.
-        return true;
-    } else if (bigramCount >= getBigramCountHardLimit(headerPolicy->getMaxBigramCount())) {
-        // Bigram count exceeds the limit.
-        return true;
+        const EntryCounts &entryCounts, const HeaderPolicy *const headerPolicy) {
+    const EntryCounts &maxNgramCounts = headerPolicy->getMaxNgramCounts();
+    for (const auto ngramType : AllNgramTypes::ASCENDING) {
+        if (entryCounts.getNgramCount(ngramType)
+                >= getEntryCountHardLimit(maxNgramCounts.getNgramCount(ngramType))) {
+            // Unigram count exceeds the limit.
+            return true;
+        }
     }
     if (mindsBlockByDecay) {
         return false;
@@ -170,7 +165,7 @@ const ForgettingCurveUtils::ProbabilityTable ForgettingCurveUtils::sProbabilityT
 
 /* static */ int ForgettingCurveUtils::clampToValidCountRange(const int count,
         const HeaderPolicy *const headerPolicy) {
-    return std::min(std::max(count, 0), headerPolicy->getForgettingCurveOccurrencesToLevelUp() - 1);
+    return std::min(std::max(count, 0), OCCURRENCES_TO_RAISE_THE_LEVEL - 1);
 }
 
 /* static */ int ForgettingCurveUtils::clampToValidLevelRange(const int level) {
@@ -187,9 +182,9 @@ const int ForgettingCurveUtils::ProbabilityTable::MODEST_PROBABILITY_TABLE_ID =
 const int ForgettingCurveUtils::ProbabilityTable::STRONG_PROBABILITY_TABLE_ID = 2;
 const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_PROBABILITY_TABLE_ID = 3;
 const int ForgettingCurveUtils::ProbabilityTable::WEAK_MAX_PROBABILITY = 127;
-const int ForgettingCurveUtils::ProbabilityTable::MODEST_BASE_PROBABILITY = 32;
-const int ForgettingCurveUtils::ProbabilityTable::STRONG_BASE_PROBABILITY = 35;
-const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_BASE_PROBABILITY = 40;
+const int ForgettingCurveUtils::ProbabilityTable::MODEST_BASE_PROBABILITY = 8;
+const int ForgettingCurveUtils::ProbabilityTable::STRONG_BASE_PROBABILITY = 9;
+const int ForgettingCurveUtils::ProbabilityTable::AGGRESSIVE_BASE_PROBABILITY = 10;
 
 
 ForgettingCurveUtils::ProbabilityTable::ProbabilityTable() : mTables() {
@@ -202,7 +197,7 @@ ForgettingCurveUtils::ProbabilityTable::ProbabilityTable() : mTables() {
             const float endProbability = getBaseProbabilityForLevel(tableId, level - 1);
             for (int timeStepCount = 0; timeStepCount <= MAX_ELAPSED_TIME_STEP_COUNT;
                     ++timeStepCount) {
-                if (level == 0) {
+                if (level < MIN_VISIBLE_LEVEL) {
                     mTables[tableId][level][timeStepCount] = NOT_A_PROBABILITY;
                     continue;
                 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h b/native/jni/src/dictionary/utils/forgetting_curve_utils.h
index 9910777b8..ddaac7e3b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h
+++ b/native/jni/src/dictionary/utils/forgetting_curve_utils.h
@@ -20,7 +20,8 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/utils/entry_counters.h"
 
 namespace latinime {
 
@@ -39,23 +40,20 @@ class ForgettingCurveUtils {
     static int decodeProbability(const HistoricalInfo *const historicalInfo,
             const HeaderPolicy *const headerPolicy);
 
-    static int getProbability(const int encodedUnigramProbability,
-            const int encodedBigramProbability);
-
     static bool needsToKeep(const HistoricalInfo *const historicalInfo,
             const HeaderPolicy *const headerPolicy);
 
-    static bool needsToDecay(const bool mindsBlockByDecay, const int unigramCount,
-            const int bigramCount, const HeaderPolicy *const headerPolicy);
+    static bool needsToDecay(const bool mindsBlockByDecay, const EntryCounts &entryCounters,
+            const HeaderPolicy *const headerPolicy);
 
-    AK_FORCE_INLINE static int getUnigramCountHardLimit(const int maxUnigramCount) {
-        return static_cast<int>(static_cast<float>(maxUnigramCount)
-                * UNIGRAM_COUNT_HARD_LIMIT_WEIGHT);
+    // TODO: Improve probability computation method and remove this.
+    static int getProbabilityBiasForNgram(const int n) {
+        return (n - 1) * MULTIPLIER_TWO_IN_PROBABILITY_SCALE;
     }
 
-    AK_FORCE_INLINE static int getBigramCountHardLimit(const int maxBigramCount) {
-        return static_cast<int>(static_cast<float>(maxBigramCount)
-                * BIGRAM_COUNT_HARD_LIMIT_WEIGHT);
+    AK_FORCE_INLINE static int getEntryCountHardLimit(const int maxEntryCount) {
+        return static_cast<int>(static_cast<float>(maxEntryCount)
+                * ENTRY_COUNT_HARD_LIMIT_WEIGHT);
     }
 
  private:
@@ -96,9 +94,10 @@ class ForgettingCurveUtils {
     static const int MIN_VISIBLE_LEVEL;
     static const int MAX_ELAPSED_TIME_STEP_COUNT;
     static const int DISCARD_LEVEL_ZERO_ENTRY_TIME_STEP_COUNT_THRESHOLD;
+    static const int OCCURRENCES_TO_RAISE_THE_LEVEL;
+    static const int DURATION_TO_LOWER_THE_LEVEL_IN_SECONDS;
 
-    static const float UNIGRAM_COUNT_HARD_LIMIT_WEIGHT;
-    static const float BIGRAM_COUNT_HARD_LIMIT_WEIGHT;
+    static const float ENTRY_COUNT_HARD_LIMIT_WEIGHT;
 
     static const ProbabilityTable sProbabilityTable;
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp b/native/jni/src/dictionary/utils/format_utils.cpp
index 1916ea560..cef3b094c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp
+++ b/native/jni/src/dictionary/utils/format_utils.cpp
@@ -14,40 +14,44 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "dictionary/utils/format_utils.h"
 
-#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+#include "dictionary/utils/byte_array_utils.h"
 
 namespace latinime {
 
 const uint32_t FormatUtils::MAGIC_NUMBER = 0x9BC13AFE;
 
 // Magic number (4 bytes), version (2 bytes), flags (2 bytes), header size (4 bytes) = 12
-const int FormatUtils::DICTIONARY_MINIMUM_SIZE = 12;
+const size_t FormatUtils::DICTIONARY_MINIMUM_SIZE = 12;
 
 /* static */ FormatUtils::FORMAT_VERSION FormatUtils::getFormatVersion(const int formatVersion) {
     switch (formatVersion) {
         case VERSION_2:
-            return VERSION_2;
+        case VERSION_201:
+            AKLOGE("Dictionary versions 2 and 201 are incompatible with this version");
+            return UNKNOWN_VERSION;
+        case VERSION_202:
+            return VERSION_202;
         case VERSION_4_ONLY_FOR_TESTING:
             return VERSION_4_ONLY_FOR_TESTING;
-        case VERSION_4:
-            return VERSION_4;
-        case VERSION_4_DEV:
-            return VERSION_4_DEV;
+        case VERSION_402:
+            return VERSION_402;
+        case VERSION_403:
+            return VERSION_403;
         default:
             return UNKNOWN_VERSION;
     }
 }
 /* static */ FormatUtils::FORMAT_VERSION FormatUtils::detectFormatVersion(
-        const uint8_t *const dict, const int dictSize) {
+        const ReadOnlyByteArrayView dictBuffer) {
     // The magic number is stored big-endian.
     // If the dictionary is less than 4 bytes, we can't even read the magic number, so we don't
     // understand this format.
-    if (dictSize < DICTIONARY_MINIMUM_SIZE) {
+    if (dictBuffer.size() < DICTIONARY_MINIMUM_SIZE) {
         return UNKNOWN_VERSION;
     }
-    const uint32_t magicNumber = ByteArrayUtils::readUint32(dict, 0);
+    const uint32_t magicNumber = ByteArrayUtils::readUint32(dictBuffer.data(), 0);
     switch (magicNumber) {
         case MAGIC_NUMBER:
             // The layout of the header is as follows:
@@ -58,7 +62,7 @@ const int FormatUtils::DICTIONARY_MINIMUM_SIZE = 12;
             // Conceptually this converts the hardcoded value of the bytes in the file into
             // the symbolic value we use in the code. But we want the constants to be the
             // same so we use them for both here.
-            return getFormatVersion(ByteArrayUtils::readUint16(dict, 4));
+            return getFormatVersion(ByteArrayUtils::readUint16(dictBuffer.data(), 4));
         default:
             return UNKNOWN_VERSION;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h b/native/jni/src/dictionary/utils/format_utils.h
index 55ad5799f..1616efcce 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
+++ b/native/jni/src/dictionary/utils/format_utils.h
@@ -20,6 +20,7 @@
 #include <cstdint>
 
 #include "defines.h"
+#include "utils/byte_array_view.h"
 
 namespace latinime {
 
@@ -30,10 +31,15 @@ class FormatUtils {
  public:
     enum FORMAT_VERSION {
         // These MUST have the same values as the relevant constants in FormatSpec.java.
+        // TODO: Remove VERSION_2 and VERSION_201 when we:
+        // * Confirm that old versions of LatinIME download old-format dictionaries
+        // * We no longer need the corresponding constants on the Java side for dicttool
         VERSION_2 = 2,
+        VERSION_201 = 201,
+        VERSION_202 = 202,
         VERSION_4_ONLY_FOR_TESTING = 399,
-        VERSION_4 = 402,
-        VERSION_4_DEV = 403,
+        VERSION_402 = 402,
+        VERSION_403 = 403,
         UNKNOWN_VERSION = -1
     };
 
@@ -42,12 +48,12 @@ class FormatUtils {
     static const uint32_t MAGIC_NUMBER;
 
     static FORMAT_VERSION getFormatVersion(const int formatVersion);
-    static FORMAT_VERSION detectFormatVersion(const uint8_t *const dict, const int dictSize);
+    static FORMAT_VERSION detectFormatVersion(const ReadOnlyByteArrayView dictBuffer);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(FormatUtils);
 
-    static const int DICTIONARY_MINIMUM_SIZE;
+    static const size_t DICTIONARY_MINIMUM_SIZE;
 };
 } // namespace latinime
 #endif /* LATINIME_FORMAT_UTILS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp b/native/jni/src/dictionary/utils/mmapped_buffer.cpp
index 4a126ff85..c5259de6d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp
+++ b/native/jni/src/dictionary/utils/mmapped_buffer.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "dictionary/utils/mmapped_buffer.h"
 
 #include <cerrno>
 #include <climits>
@@ -23,7 +23,7 @@
 #include <sys/mman.h>
 #include <unistd.h>
 
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+#include "dictionary/utils/file_utils.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.h b/native/jni/src/dictionary/utils/mmapped_buffer.h
index e25310373..e25310373 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.h
+++ b/native/jni/src/dictionary/utils/mmapped_buffer.h
diff --git a/native/jni/src/suggest/core/dictionary/multi_bigram_map.cpp b/native/jni/src/dictionary/utils/multi_bigram_map.cpp
index 91f33a8dd..e730fff8e 100644
--- a/native/jni/src/suggest/core/dictionary/multi_bigram_map.cpp
+++ b/native/jni/src/dictionary/utils/multi_bigram_map.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/core/dictionary/multi_bigram_map.h"
+#include "dictionary/utils/multi_bigram_map.h"
 
 #include <cstddef>
 #include <unordered_map>
@@ -35,39 +35,37 @@ const int MultiBigramMap::BigramMap::DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP =
 // Also caches the bigrams if there is space remaining and they have not been cached already.
 int MultiBigramMap::getBigramProbability(
         const DictionaryStructureWithBufferPolicy *const structurePolicy,
-        const int *const prevWordsPtNodePos, const int nextWordPosition,
+        const WordIdArrayView prevWordIds, const int nextWordId,
         const int unigramProbability) {
-    if (!prevWordsPtNodePos || prevWordsPtNodePos[0] == NOT_A_DICT_POS) {
+    if (prevWordIds.empty() || prevWordIds[0] == NOT_A_WORD_ID) {
         return structurePolicy->getProbability(unigramProbability, NOT_A_PROBABILITY);
     }
-    std::unordered_map<int, BigramMap>::const_iterator mapPosition =
-            mBigramMaps.find(prevWordsPtNodePos[0]);
+    const auto mapPosition = mBigramMaps.find(prevWordIds[0]);
     if (mapPosition != mBigramMaps.end()) {
-        return mapPosition->second.getBigramProbability(structurePolicy, nextWordPosition,
+        return mapPosition->second.getBigramProbability(structurePolicy, nextWordId,
                 unigramProbability);
     }
     if (mBigramMaps.size() < MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP) {
-        addBigramsForWordPosition(structurePolicy, prevWordsPtNodePos);
-        return mBigramMaps[prevWordsPtNodePos[0]].getBigramProbability(structurePolicy,
-                nextWordPosition, unigramProbability);
+        addBigramsForWord(structurePolicy, prevWordIds);
+        return mBigramMaps[prevWordIds[0]].getBigramProbability(structurePolicy,
+                nextWordId, unigramProbability);
     }
-    return readBigramProbabilityFromBinaryDictionary(structurePolicy, prevWordsPtNodePos,
-            nextWordPosition, unigramProbability);
+    return readBigramProbabilityFromBinaryDictionary(structurePolicy, prevWordIds,
+            nextWordId, unigramProbability);
 }
 
 void MultiBigramMap::BigramMap::init(
         const DictionaryStructureWithBufferPolicy *const structurePolicy,
-        const int *const prevWordsPtNodePos) {
-    structurePolicy->iterateNgramEntries(prevWordsPtNodePos, this /* listener */);
+        const WordIdArrayView prevWordIds) {
+    structurePolicy->iterateNgramEntries(prevWordIds, this /* listener */);
 }
 
 int MultiBigramMap::BigramMap::getBigramProbability(
         const DictionaryStructureWithBufferPolicy *const structurePolicy,
-        const int nextWordPosition, const int unigramProbability) const {
+        const int nextWordId, const int unigramProbability) const {
     int bigramProbability = NOT_A_PROBABILITY;
-    if (mBloomFilter.isInFilter(nextWordPosition)) {
-        const std::unordered_map<int, int>::const_iterator bigramProbabilityIt =
-                mBigramMap.find(nextWordPosition);
+    if (mBloomFilter.isInFilter(nextWordId)) {
+        const auto bigramProbabilityIt = mBigramMap.find(nextWordId);
         if (bigramProbabilityIt != mBigramMap.end()) {
             bigramProbability = bigramProbabilityIt->second;
         }
@@ -75,29 +73,24 @@ int MultiBigramMap::BigramMap::getBigramProbability(
     return structurePolicy->getProbability(unigramProbability, bigramProbability);
 }
 
-void MultiBigramMap::BigramMap::onVisitEntry(const int ngramProbability,
-        const int targetPtNodePos) {
-    if (targetPtNodePos == NOT_A_DICT_POS) {
+void MultiBigramMap::BigramMap::onVisitEntry(const int ngramProbability, const int targetWordId) {
+    if (targetWordId == NOT_A_WORD_ID) {
         return;
     }
-    mBigramMap[targetPtNodePos] = ngramProbability;
-    mBloomFilter.setInFilter(targetPtNodePos);
+    mBigramMap[targetWordId] = ngramProbability;
+    mBloomFilter.setInFilter(targetWordId);
 }
 
-void MultiBigramMap::addBigramsForWordPosition(
+void MultiBigramMap::addBigramsForWord(
         const DictionaryStructureWithBufferPolicy *const structurePolicy,
-        const int *const prevWordsPtNodePos) {
-    if (prevWordsPtNodePos) {
-        mBigramMaps[prevWordsPtNodePos[0]].init(structurePolicy, prevWordsPtNodePos);
-    }
+        const WordIdArrayView prevWordIds) {
+    mBigramMaps[prevWordIds[0]].init(structurePolicy, prevWordIds);
 }
 
 int MultiBigramMap::readBigramProbabilityFromBinaryDictionary(
         const DictionaryStructureWithBufferPolicy *const structurePolicy,
-        const int *const prevWordsPtNodePos, const int nextWordPosition,
-        const int unigramProbability) {
-    const int bigramProbability = structurePolicy->getProbabilityOfPtNode(prevWordsPtNodePos,
-            nextWordPosition);
+        const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability) {
+    const int bigramProbability = structurePolicy->getProbabilityOfWord(prevWordIds, nextWordId);
     if (bigramProbability != NOT_A_PROBABILITY) {
         return bigramProbability;
     }
diff --git a/native/jni/src/suggest/core/dictionary/multi_bigram_map.h b/native/jni/src/dictionary/utils/multi_bigram_map.h
index ad36dde83..6f23d98bc 100644
--- a/native/jni/src/suggest/core/dictionary/multi_bigram_map.h
+++ b/native/jni/src/dictionary/utils/multi_bigram_map.h
@@ -21,10 +21,11 @@
 #include <unordered_map>
 
 #include "defines.h"
-#include "suggest/core/dictionary/binary_dictionary_bigrams_iterator.h"
-#include "suggest/core/dictionary/bloom_filter.h"
-#include "suggest/core/dictionary/ngram_listener.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/interface/ngram_listener.h"
+#include "dictionary/utils/binary_dictionary_bigrams_iterator.h"
+#include "dictionary/utils/bloom_filter.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -39,8 +40,7 @@ class MultiBigramMap {
     // Look up the bigram probability for the given word pair from the cached bigram maps.
     // Also caches the bigrams if there is space remaining and they have not been cached already.
     int getBigramProbability(const DictionaryStructureWithBufferPolicy *const structurePolicy,
-            const int *const prevWordsPtNodePos, const int nextWordPosition,
-            const int unigramProbability);
+            const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability);
 
     void clear() {
         mBigramMaps.clear();
@@ -58,11 +58,11 @@ class MultiBigramMap {
         virtual ~BigramMap() {}
 
         void init(const DictionaryStructureWithBufferPolicy *const structurePolicy,
-                const int *const prevWordsPtNodePos);
+                const WordIdArrayView prevWordIds);
         int getBigramProbability(
                 const DictionaryStructureWithBufferPolicy *const structurePolicy,
-                const int nextWordPosition, const int unigramProbability) const;
-        virtual void onVisitEntry(const int ngramProbability, const int targetPtNodePos);
+                const int nextWordId, const int unigramProbability) const;
+        virtual void onVisitEntry(const int ngramProbability, const int targetWordId);
 
      private:
         static const int DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP;
@@ -70,14 +70,12 @@ class MultiBigramMap {
         BloomFilter mBloomFilter;
     };
 
-    void addBigramsForWordPosition(
-            const DictionaryStructureWithBufferPolicy *const structurePolicy,
-            const int *const prevWordsPtNodePos);
+    void addBigramsForWord(const DictionaryStructureWithBufferPolicy *const structurePolicy,
+            const WordIdArrayView prevWordIds);
 
     int readBigramProbabilityFromBinaryDictionary(
             const DictionaryStructureWithBufferPolicy *const structurePolicy,
-            const int *const prevWordsPtNodePos, const int nextWordPosition,
-            const int unigramProbability);
+            const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability);
 
     static const size_t MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP;
     std::unordered_map<int, BigramMap> mBigramMaps;
diff --git a/native/jni/src/dictionary/utils/probability_utils.cpp b/native/jni/src/dictionary/utils/probability_utils.cpp
new file mode 100644
index 000000000..426a0e783
--- /dev/null
+++ b/native/jni/src/dictionary/utils/probability_utils.cpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dictionary/utils/probability_utils.h"
+
+namespace latinime {
+
+const float ProbabilityUtils::PROBABILITY_ENCODING_SCALER = 8.58923700372f;
+
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/probability_utils.h b/native/jni/src/dictionary/utils/probability_utils.h
index 3b339e61a..2050af1e9 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/probability_utils.h
+++ b/native/jni/src/dictionary/utils/probability_utils.h
@@ -17,6 +17,9 @@
 #ifndef LATINIME_PROBABILITY_UTILS_H
 #define LATINIME_PROBABILITY_UTILS_H
 
+#include <algorithm>
+#include <cmath>
+
 #include "defines.h"
 
 namespace latinime {
@@ -47,8 +50,20 @@ class ProbabilityUtils {
                 + static_cast<int>(static_cast<float>(bigramProbability + 1) * stepSize);
     }
 
+    // Encode probability using the same way as we are doing for main dictionaries.
+    static AK_FORCE_INLINE int encodeRawProbability(const float rawProbability) {
+        const float probability = static_cast<float>(MAX_PROBABILITY)
+                + log2f(rawProbability) * PROBABILITY_ENCODING_SCALER;
+        if (probability < 0.0f) {
+            return 0;
+        }
+        return std::min(static_cast<int>(probability + 0.5f), MAX_PROBABILITY);
+    }
+
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(ProbabilityUtils);
+
+    static const float PROBABILITY_ENCODING_SCALER;
 };
 }
 #endif /* LATINIME_PROBABILITY_UTILS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/sparse_table.cpp b/native/jni/src/dictionary/utils/sparse_table.cpp
index d336306b9..029329fab 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/sparse_table.cpp
+++ b/native/jni/src/dictionary/utils/sparse_table.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/sparse_table.h"
+#include "dictionary/utils/sparse_table.h"
 
 namespace latinime {
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/sparse_table.h b/native/jni/src/dictionary/utils/sparse_table.h
index fca8120f1..bd1190e8b 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/sparse_table.h
+++ b/native/jni/src/dictionary/utils/sparse_table.h
@@ -20,11 +20,10 @@
 #include <cstdint>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 
 namespace latinime {
 
-// Note that there is a corresponding implementation in SparseTable.java.
 // TODO: Support multiple content buffers.
 class SparseTable {
  public:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/trie_map.cpp b/native/jni/src/dictionary/utils/trie_map.cpp
index 407b8efd0..0bef8c702 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/trie_map.cpp
+++ b/native/jni/src/dictionary/utils/trie_map.cpp
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#include "suggest/policyimpl/dictionary/utils/trie_map.h"
+#include "dictionary/utils/trie_map.h"
 
-#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "dictionary/utils/dict_file_writing_utils.h"
 
 namespace latinime {
 
@@ -26,6 +26,7 @@ const int TrieMap::FIELD1_SIZE = 3;
 const int TrieMap::ENTRY_SIZE = FIELD0_SIZE + FIELD1_SIZE;
 const uint32_t TrieMap::VALUE_FLAG = 0x400000;
 const uint32_t TrieMap::VALUE_MASK = 0x3FFFFF;
+const uint32_t TrieMap::INVALID_VALUE_IN_KEY_VALUE_ENTRY = VALUE_MASK;
 const uint32_t TrieMap::TERMINAL_LINK_FLAG = 0x800000;
 const uint32_t TrieMap::TERMINAL_LINK_MASK = 0x7FFFFF;
 const int TrieMap::NUM_OF_BITS_USED_FOR_ONE_LEVEL = 5;
@@ -34,6 +35,7 @@ const int TrieMap::MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL = 1 << NUM_OF_BITS_USED_FOR_O
 const int TrieMap::ROOT_BITMAP_ENTRY_INDEX = 0;
 const int TrieMap::ROOT_BITMAP_ENTRY_POS = MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL * FIELD0_SIZE;
 const TrieMap::Entry TrieMap::EMPTY_BITMAP_ENTRY = TrieMap::Entry(0, 0);
+const int TrieMap::TERMINAL_LINKED_ENTRY_COUNT = 2; // Value entry and bitmap entry.
 const uint64_t TrieMap::MAX_VALUE =
         (static_cast<uint64_t>(1) << ((FIELD0_SIZE + FIELD1_SIZE) * CHAR_BIT)) - 1;
 const int TrieMap::MAX_BUFFER_SIZE = TERMINAL_LINK_MASK * ENTRY_SIZE;
@@ -76,14 +78,17 @@ int TrieMap::getNextLevelBitmapEntryIndex(const int key, const int bitmapEntryIn
         return terminalEntry.getValueEntryIndex() + 1;
     }
     // Create a value entry and a bitmap entry.
-    const int valueEntryIndex = allocateTable(2 /* entryCount */);
+    const int valueEntryIndex = allocateTable(TERMINAL_LINKED_ENTRY_COUNT);
+    if (valueEntryIndex == INVALID_INDEX) {
+        return INVALID_INDEX;
+    }
     if (!writeEntry(Entry(0, terminalEntry.getValue()), valueEntryIndex)) {
         return INVALID_INDEX;
     }
     if (!writeEntry(EMPTY_BITMAP_ENTRY, valueEntryIndex + 1)) {
         return INVALID_INDEX;
     }
-    if (!writeField1(valueEntryIndex | TERMINAL_LINK_FLAG, valueEntryIndex)) {
+    if (!writeField1(valueEntryIndex | TERMINAL_LINK_FLAG, terminalEntryIndex)) {
         return INVALID_INDEX;
     }
     return valueEntryIndex + 1;
@@ -108,6 +113,31 @@ bool TrieMap::save(FILE *const file) const {
     return DictFileWritingUtils::writeBufferToFileTail(file, &mBuffer);
 }
 
+bool TrieMap::remove(const int key, const int bitmapEntryIndex) {
+    const Entry bitmapEntry = readEntry(bitmapEntryIndex);
+    const uint32_t unsignedKey = static_cast<uint32_t>(key);
+    const int terminalEntryIndex = getTerminalEntryIndex(
+            unsignedKey, getBitShuffledKey(unsignedKey), bitmapEntry, 0 /* level */);
+    if (terminalEntryIndex == INVALID_INDEX) {
+        // Not found.
+        return false;
+    }
+    const Entry terminalEntry = readEntry(terminalEntryIndex);
+    if (!writeField1(VALUE_FLAG ^ INVALID_VALUE_IN_KEY_VALUE_ENTRY , terminalEntryIndex)) {
+        return false;
+    }
+    if (terminalEntry.hasTerminalLink()) {
+        const Entry nextLevelBitmapEntry = readEntry(terminalEntry.getValueEntryIndex() + 1);
+        if (!freeTable(terminalEntry.getValueEntryIndex(), TERMINAL_LINKED_ENTRY_COUNT)) {
+            return false;
+        }
+        if (!removeInner(nextLevelBitmapEntry)){
+            return false;
+        }
+    }
+    return true;
+}
+
 /**
  * Iterate next entry in a certain level.
  *
@@ -129,7 +159,7 @@ const TrieMap::Result TrieMap::iterateNext(std::vector<TableIterationState> *con
             if (entry.isBitmapEntry()) {
                 // Move to child.
                 iterationState->emplace_back(popCount(entry.getBitmap()), entry.getTableIndex());
-            } else {
+            } else if (entry.isValidTerminalEntry()) {
                 if (outKey) {
                     *outKey = entry.getKey();
                 }
@@ -162,12 +192,15 @@ uint32_t TrieMap::getBitShuffledKey(const uint32_t key) const {
 }
 
 bool TrieMap::writeValue(const uint64_t value, const int terminalEntryIndex) {
-    if (value <= VALUE_MASK) {
+    if (value < VALUE_MASK) {
         // Write value into the terminal entry.
         return writeField1(value | VALUE_FLAG, terminalEntryIndex);
     }
     // Create value entry and write value.
-    const int valueEntryIndex = allocateTable(2 /* entryCount */);
+    const int valueEntryIndex = allocateTable(TERMINAL_LINKED_ENTRY_COUNT);
+    if (valueEntryIndex == INVALID_INDEX) {
+        return false;
+    }
     if (!writeEntry(Entry(value >> (FIELD1_SIZE * CHAR_BIT), value), valueEntryIndex)) {
         return false;
     }
@@ -227,6 +260,9 @@ int TrieMap::getTerminalEntryIndex(const uint32_t key, const uint32_t hashedKey,
         // Move to the next level.
         return getTerminalEntryIndex(key, hashedKey, entry, level + 1);
     }
+    if (!entry.isValidTerminalEntry()) {
+        return INVALID_INDEX;
+    }
     if (entry.getKey() == key) {
         // Terminal entry is found.
         return entryIndex;
@@ -287,6 +323,10 @@ bool TrieMap::putInternal(const uint32_t key, const uint64_t value, const uint32
         // Bitmap entry is found. Go to the next level.
         return putInternal(key, value, hashedKey, entryIndex, entry, level + 1);
     }
+    if (!entry.isValidTerminalEntry()) {
+        // Overwrite invalid terminal entry.
+        return writeTerminalEntry(key, value, entryIndex);
+    }
     if (entry.getKey() == key) {
         // Terminal entry for the key is found. Update the value.
         return updateValue(entry, value, entryIndex);
@@ -384,4 +424,37 @@ bool TrieMap::addNewEntryByExpandingTable(const uint32_t key, const uint64_t val
     return true;
 }
 
+bool TrieMap::removeInner(const Entry &bitmapEntry) {
+    const int tableSize = popCount(bitmapEntry.getBitmap());
+    if (tableSize <= 0) {
+        // The table is empty. No need to remove any entries.
+        return true;
+    }
+    for (int i = 0; i < tableSize; ++i) {
+        const int entryIndex = bitmapEntry.getTableIndex() + i;
+        const Entry entry = readEntry(entryIndex);
+        if (entry.isBitmapEntry()) {
+            // Delete next bitmap entry recursively.
+            if (!removeInner(entry)) {
+                return false;
+            }
+        } else {
+            // Invalidate terminal entry just in case.
+            if (!writeField1(VALUE_FLAG ^ INVALID_VALUE_IN_KEY_VALUE_ENTRY , entryIndex)) {
+                return false;
+            }
+            if (entry.hasTerminalLink()) {
+                const Entry nextLevelBitmapEntry = readEntry(entry.getValueEntryIndex() + 1);
+                if (!freeTable(entry.getValueEntryIndex(), TERMINAL_LINKED_ENTRY_COUNT)) {
+                    return false;
+                }
+                if (!removeInner(nextLevelBitmapEntry)) {
+                    return false;
+                }
+            }
+        }
+    }
+    return true;
+}
+
 }  // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/trie_map.h b/native/jni/src/dictionary/utils/trie_map.h
index 3e5c4010c..5fc6c2690 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/trie_map.h
+++ b/native/jni/src/dictionary/utils/trie_map.h
@@ -23,7 +23,7 @@
 #include <vector>
 
 #include "defines.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "dictionary/utils/buffer_with_extendable_buffer.h"
 #include "utils/byte_array_view.h"
 
 namespace latinime {
@@ -84,6 +84,10 @@ class TrieMap {
                 return mValue;
             }
 
+            AK_FORCE_INLINE int getNextLevelBitmapEntryIndex() const {
+                return mNextLevelBitmapEntryIndex;
+            }
+
          private:
             const TrieMap *const mTrieMap;
             const int mKey;
@@ -94,7 +98,7 @@ class TrieMap {
         TrieMapIterator(const TrieMap *const trieMap, const int bitmapEntryIndex)
                 : mTrieMap(trieMap), mStateStack(), mBaseBitmapEntryIndex(bitmapEntryIndex),
                   mKey(0), mValue(0), mIsValid(false), mNextLevelBitmapEntryIndex(INVALID_INDEX) {
-            if (!trieMap) {
+            if (!trieMap || mBaseBitmapEntryIndex == INVALID_INDEX) {
                 return;
             }
             const Entry bitmapEntry = mTrieMap->readEntry(mBaseBitmapEntryIndex);
@@ -202,6 +206,8 @@ class TrieMap {
 
     bool save(FILE *const file) const;
 
+    bool remove(const int key, const int bitmapEntryIndex);
+
  private:
     DISALLOW_COPY_AND_ASSIGN(TrieMap);
 
@@ -245,6 +251,11 @@ class TrieMap {
         }
 
         // For terminal entry.
+        AK_FORCE_INLINE bool isValidTerminalEntry() const {
+            return hasTerminalLink() || ((mData1 & VALUE_MASK) != INVALID_VALUE_IN_KEY_VALUE_ENTRY);
+        }
+
+        // For terminal entry.
         AK_FORCE_INLINE uint32_t getValueEntryIndex() const {
             return mData1 & TERMINAL_LINK_MASK;
         }
@@ -272,6 +283,7 @@ class TrieMap {
     static const int ENTRY_SIZE;
     static const uint32_t VALUE_FLAG;
     static const uint32_t VALUE_MASK;
+    static const uint32_t INVALID_VALUE_IN_KEY_VALUE_ENTRY;
     static const uint32_t TERMINAL_LINK_FLAG;
     static const uint32_t TERMINAL_LINK_MASK;
     static const int NUM_OF_BITS_USED_FOR_ONE_LEVEL;
@@ -280,6 +292,7 @@ class TrieMap {
     static const int ROOT_BITMAP_ENTRY_INDEX;
     static const int ROOT_BITMAP_ENTRY_POS;
     static const Entry EMPTY_BITMAP_ENTRY;
+    static const int TERMINAL_LINKED_ENTRY_COUNT;
     static const int MAX_BUFFER_SIZE;
 
     uint32_t getBitShuffledKey(const uint32_t key) const;
@@ -378,6 +391,8 @@ class TrieMap {
     AK_FORCE_INLINE int getTailEntryIndex() const {
         return (mBuffer.getTailPosition() - ROOT_BITMAP_ENTRY_POS) / ENTRY_SIZE;
     }
+
+    bool removeInner(const Entry &bitmapEntry);
 };
 
 } // namespace latinime
diff --git a/native/jni/src/suggest/core/dicnode/dic_node.h b/native/jni/src/suggest/core/dicnode/dic_node.h
index d1b2c87be..5214077dc 100644
--- a/native/jni/src/suggest/core/dicnode/dic_node.h
+++ b/native/jni/src/suggest/core/dicnode/dic_node.h
@@ -26,6 +26,7 @@
 #include "suggest/core/dictionary/error_type_utils.h"
 #include "suggest/core/layout/proximity_info_state.h"
 #include "utils/char_utils.h"
+#include "utils/int_array_view.h"
 
 #if DEBUG_DICT
 #define LOGI_SHOW_ADD_COST_PROP \
@@ -103,10 +104,10 @@ class DicNode {
         PROF_NODE_COPY(&dicNode->mProfiler, mProfiler);
     }
 
-    // Init for root with prevWordsPtNodePos which is used for n-gram
-    void initAsRoot(const int rootPtNodeArrayPos, const int *const prevWordsPtNodePos) {
+    // Init for root with prevWordIds which is used for n-gram
+    void initAsRoot(const int rootPtNodeArrayPos, const WordIdArrayView prevWordIds) {
         mIsCachedForNextSuggestion = false;
-        mDicNodeProperties.init(rootPtNodeArrayPos, prevWordsPtNodePos);
+        mDicNodeProperties.init(rootPtNodeArrayPos, prevWordIds);
         mDicNodeState.init();
         PROF_NODE_RESET(mProfiler);
     }
@@ -114,12 +115,11 @@ class DicNode {
     // Init for root with previous word
     void initAsRootWithPreviousWord(const DicNode *const dicNode, const int rootPtNodeArrayPos) {
         mIsCachedForNextSuggestion = dicNode->mIsCachedForNextSuggestion;
-        int newPrevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-        newPrevWordsPtNodePos[0] = dicNode->mDicNodeProperties.getPtNodePos();
-        for (size_t i = 1; i < NELEMS(newPrevWordsPtNodePos); ++i) {
-            newPrevWordsPtNodePos[i] = dicNode->getPrevWordsTerminalPtNodePos()[i - 1];
-        }
-        mDicNodeProperties.init(rootPtNodeArrayPos, newPrevWordsPtNodePos);
+        WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> newPrevWordIds;
+        newPrevWordIds[0] = dicNode->mDicNodeProperties.getWordId();
+        dicNode->getPrevWordIds().limit(newPrevWordIds.size() - 1)
+                .copyToArray(&newPrevWordIds, 1 /* offset */);
+        mDicNodeProperties.init(rootPtNodeArrayPos, WordIdArrayView::fromArray(newPrevWordIds));
         mDicNodeState.initAsRootWithPreviousWord(&dicNode->mDicNodeState,
                 dicNode->mDicNodeProperties.getDepth());
         PROF_NODE_COPY(&dicNode->mProfiler, mProfiler);
@@ -135,19 +135,16 @@ class DicNode {
         PROF_NODE_COPY(&parentDicNode->mProfiler, mProfiler);
     }
 
-    void initAsChild(const DicNode *const dicNode, const int ptNodePos,
-            const int childrenPtNodeArrayPos, const int probability, const bool isTerminal,
-            const bool hasChildren, const bool isBlacklistedOrNotAWord,
-            const uint16_t mergedNodeCodePointCount, const int *const mergedNodeCodePoints) {
+    void initAsChild(const DicNode *const dicNode, const int childrenPtNodeArrayPos,
+            const int wordId, const CodePointArrayView mergedCodePoints) {
         uint16_t newDepth = static_cast<uint16_t>(dicNode->getNodeCodePointCount() + 1);
         mIsCachedForNextSuggestion = dicNode->mIsCachedForNextSuggestion;
         const uint16_t newLeavingDepth = static_cast<uint16_t>(
-                dicNode->mDicNodeProperties.getLeavingDepth() + mergedNodeCodePointCount);
-        mDicNodeProperties.init(ptNodePos, childrenPtNodeArrayPos, mergedNodeCodePoints[0],
-                probability, isTerminal, hasChildren, isBlacklistedOrNotAWord, newDepth,
-                newLeavingDepth, dicNode->mDicNodeProperties.getPrevWordsTerminalPtNodePos());
-        mDicNodeState.init(&dicNode->mDicNodeState, mergedNodeCodePointCount,
-                mergedNodeCodePoints);
+                dicNode->mDicNodeProperties.getLeavingDepth() + mergedCodePoints.size());
+        mDicNodeProperties.init(childrenPtNodeArrayPos, mergedCodePoints[0],
+                wordId, newDepth, newLeavingDepth, dicNode->mDicNodeProperties.getPrevWordIds());
+        mDicNodeState.init(&dicNode->mDicNodeState, mergedCodePoints.size(),
+                mergedCodePoints.data());
         PROF_NODE_COPY(&dicNode->mProfiler, mProfiler);
     }
 
@@ -179,9 +176,6 @@ class DicNode {
     // Check if the current word and the previous word can be considered as a valid multiple word
     // suggestion.
     bool isValidMultipleWordSuggestion() const {
-        if (isBlacklistedOrNotAWord()) {
-            return false;
-        }
         // Treat suggestion as invalid if the current and the previous word are single character
         // words.
         const int prevWordLen = mDicNodeState.mDicNodeStateOutput.getPrevWordsLength()
@@ -204,13 +198,12 @@ class DicNode {
     }
 
     // Used to get n-gram probability in DicNodeUtils.
-    int getPtNodePos() const {
-        return mDicNodeProperties.getPtNodePos();
+    int getWordId() const {
+        return mDicNodeProperties.getWordId();
     }
 
-    // TODO: Use view class to return PtNodePos array.
-    const int *getPrevWordsTerminalPtNodePos() const {
-        return mDicNodeProperties.getPrevWordsTerminalPtNodePos();
+    const WordIdArrayView getPrevWordIds() const {
+        return mDicNodeProperties.getPrevWordIds();
     }
 
     // Used in DicNodeUtils
@@ -218,10 +211,6 @@ class DicNode {
         return mDicNodeProperties.getChildrenPtNodeArrayPos();
     }
 
-    int getProbability() const {
-        return mDicNodeProperties.getProbability();
-    }
-
     AK_FORCE_INLINE bool isTerminalDicNode() const {
         const bool isTerminalPtNode = mDicNodeProperties.isTerminal();
         const int currentDicNodeDepth = getNodeCodePointCount();
@@ -306,8 +295,9 @@ class DicNode {
     }
 
     // Used to prune nodes
-    float getCompoundDistance(const float languageWeight) const {
-        return mDicNodeState.mDicNodeStateScoring.getCompoundDistance(languageWeight);
+    float getCompoundDistance(const float weightOfLangModelVsSpatialModel) const {
+        return mDicNodeState.mDicNodeStateScoring.getCompoundDistance(
+                weightOfLangModelVsSpatialModel);
     }
 
     AK_FORCE_INLINE const int *getOutputWordBuf() const {
@@ -404,10 +394,6 @@ class DicNode {
         return mDicNodeState.mDicNodeStateScoring.getContainedErrorTypes();
     }
 
-    bool isBlacklistedOrNotAWord() const {
-        return mDicNodeProperties.isBlacklistedOrNotAWord();
-    }
-
     inline uint16_t getNodeCodePointCount() const {
         return mDicNodeProperties.getDepth();
     }
diff --git a/native/jni/src/suggest/core/dicnode/dic_node_utils.cpp b/native/jni/src/suggest/core/dicnode/dic_node_utils.cpp
index 69ea67418..a20252cd2 100644
--- a/native/jni/src/suggest/core/dicnode/dic_node_utils.cpp
+++ b/native/jni/src/suggest/core/dicnode/dic_node_utils.cpp
@@ -16,10 +16,9 @@
 
 #include "suggest/core/dicnode/dic_node_utils.h"
 
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_vector.h"
-#include "suggest/core/dictionary/multi_bigram_map.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
 
 namespace latinime {
 
@@ -29,8 +28,8 @@ namespace latinime {
 
 /* static */ void DicNodeUtils::initAsRoot(
         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-        const int *const prevWordsPtNodePos, DicNode *const newRootDicNode) {
-    newRootDicNode->initAsRoot(dictionaryStructurePolicy->getRootPosition(), prevWordsPtNodePos);
+        const WordIdArrayView prevWordIds, DicNode *const newRootDicNode) {
+    newRootDicNode->initAsRoot(dictionaryStructurePolicy->getRootPosition(), prevWordIds);
 }
 
 /*static */ void DicNodeUtils::initAsRootWithPreviousWord(
@@ -73,25 +72,17 @@ namespace latinime {
     if (dicNode->hasMultipleWords() && !dicNode->isValidMultipleWordSuggestion()) {
         return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
     }
-    const int probability = getBigramNodeProbability(dictionaryStructurePolicy, dicNode,
-            multiBigramMap);
+    const WordAttributes wordAttributes = dictionaryStructurePolicy->getWordAttributesInContext(
+            dicNode->getPrevWordIds(), dicNode->getWordId(), multiBigramMap);
+    if (wordAttributes.getProbability() == NOT_A_PROBABILITY
+            || (dicNode->hasMultipleWords()
+                    && (wordAttributes.isBlacklisted() || wordAttributes.isNotAWord()))) {
+        return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
+    }
     // TODO: This equation to calculate the improbability looks unreasonable.  Investigate this.
-    const float cost = static_cast<float>(MAX_PROBABILITY - probability)
+    const float cost = static_cast<float>(MAX_PROBABILITY - wordAttributes.getProbability())
             / static_cast<float>(MAX_PROBABILITY);
     return cost;
 }
 
-/* static */ int DicNodeUtils::getBigramNodeProbability(
-        const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-        const DicNode *const dicNode, MultiBigramMap *const multiBigramMap) {
-    const int unigramProbability = dicNode->getProbability();
-    if (multiBigramMap) {
-        const int *const prevWordsPtNodePos = dicNode->getPrevWordsTerminalPtNodePos();
-        return multiBigramMap->getBigramProbability(dictionaryStructurePolicy,
-                prevWordsPtNodePos, dicNode->getPtNodePos(), unigramProbability);
-    }
-    return dictionaryStructurePolicy->getProbability(unigramProbability,
-            NOT_A_PROBABILITY);
-}
-
 } // namespace latinime
diff --git a/native/jni/src/suggest/core/dicnode/dic_node_utils.h b/native/jni/src/suggest/core/dicnode/dic_node_utils.h
index 00e80c604..b891a842a 100644
--- a/native/jni/src/suggest/core/dicnode/dic_node_utils.h
+++ b/native/jni/src/suggest/core/dicnode/dic_node_utils.h
@@ -18,6 +18,7 @@
 #define LATINIME_DIC_NODE_UTILS_H
 
 #include "defines.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -30,7 +31,7 @@ class DicNodeUtils {
  public:
     static void initAsRoot(
             const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-            const int *const prevWordPtNodePos, DicNode *const newRootDicNode);
+            const WordIdArrayView prevWordIds, DicNode *const newRootDicNode);
     static void initAsRootWithPreviousWord(
             const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
             const DicNode *const prevWordLastDicNode, DicNode *const newRootDicNode);
@@ -46,10 +47,6 @@ class DicNodeUtils {
     DISALLOW_IMPLICIT_CONSTRUCTORS(DicNodeUtils);
     // Max number of bigrams to look up
     static const int MAX_BIGRAMS_CONSIDERED_PER_CONTEXT = 500;
-
-    static int getBigramNodeProbability(
-            const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-            const DicNode *const dicNode, MultiBigramMap *const multiBigramMap);
 };
 } // namespace latinime
 #endif // LATINIME_DIC_NODE_UTILS_H
diff --git a/native/jni/src/suggest/core/dicnode/dic_node_vector.h b/native/jni/src/suggest/core/dicnode/dic_node_vector.h
index 54cde1988..e6b758954 100644
--- a/native/jni/src/suggest/core/dicnode/dic_node_vector.h
+++ b/native/jni/src/suggest/core/dicnode/dic_node_vector.h
@@ -21,6 +21,7 @@
 
 #include "defines.h"
 #include "suggest/core/dicnode/dic_node.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -58,15 +59,11 @@ class DicNodeVector {
         mDicNodes.back().initAsPassingChild(dicNode);
     }
 
-    void pushLeavingChild(const DicNode *const dicNode, const int ptNodePos,
-            const int childrenPtNodeArrayPos, const int probability, const bool isTerminal,
-            const bool hasChildren, const bool isBlacklistedOrNotAWord,
-            const uint16_t mergedNodeCodePointCount, const int *const mergedNodeCodePoints) {
+    void pushLeavingChild(const DicNode *const dicNode, const int childrenPtNodeArrayPos,
+            const int wordId, const CodePointArrayView mergedCodePoints) {
         ASSERT(!mLock);
         mDicNodes.emplace_back();
-        mDicNodes.back().initAsChild(dicNode, ptNodePos, childrenPtNodeArrayPos, probability,
-                isTerminal, hasChildren, isBlacklistedOrNotAWord, mergedNodeCodePointCount,
-                mergedNodeCodePoints);
+        mDicNodes.back().initAsChild(dicNode, childrenPtNodeArrayPos, wordId, mergedCodePoints);
     }
 
     DicNode *operator[](const int id) {
diff --git a/native/jni/src/suggest/core/dicnode/internal/dic_node_properties.h b/native/jni/src/suggest/core/dicnode/internal/dic_node_properties.h
index 8202176f7..1b796b5d4 100644
--- a/native/jni/src/suggest/core/dicnode/internal/dic_node_properties.h
+++ b/native/jni/src/suggest/core/dicnode/internal/dic_node_properties.h
@@ -18,8 +18,10 @@
 #define LATINIME_DIC_NODE_PROPERTIES_H
 
 #include <cstdint>
+#include <cstdlib>
 
 #include "defines.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -29,84 +31,61 @@ namespace latinime {
 class DicNodeProperties {
  public:
     AK_FORCE_INLINE DicNodeProperties()
-            : mPtNodePos(NOT_A_DICT_POS), mChildrenPtNodeArrayPos(NOT_A_DICT_POS),
-              mProbability(NOT_A_PROBABILITY), mDicNodeCodePoint(NOT_A_CODE_POINT),
-              mIsTerminal(false), mHasChildrenPtNodes(false),
-              mIsBlacklistedOrNotAWord(false), mDepth(0), mLeavingDepth(0) {}
+            : mChildrenPtNodeArrayPos(NOT_A_DICT_POS), mDicNodeCodePoint(NOT_A_CODE_POINT),
+              mWordId(NOT_A_WORD_ID), mDepth(0), mLeavingDepth(0), mPrevWordCount(0) {}
 
     ~DicNodeProperties() {}
 
     // Should be called only once per DicNode is initialized.
-    void init(const int pos, const int childrenPos, const int nodeCodePoint, const int probability,
-            const bool isTerminal, const bool hasChildren, const bool isBlacklistedOrNotAWord,
-            const uint16_t depth, const uint16_t leavingDepth, const int *const prevWordsNodePos) {
-        mPtNodePos = pos;
+    void init(const int childrenPos, const int nodeCodePoint, const int wordId,
+            const uint16_t depth, const uint16_t leavingDepth, const WordIdArrayView prevWordIds) {
         mChildrenPtNodeArrayPos = childrenPos;
         mDicNodeCodePoint = nodeCodePoint;
-        mProbability = probability;
-        mIsTerminal = isTerminal;
-        mHasChildrenPtNodes = hasChildren;
-        mIsBlacklistedOrNotAWord = isBlacklistedOrNotAWord;
+        mWordId = wordId;
         mDepth = depth;
         mLeavingDepth = leavingDepth;
-        memmove(mPrevWordsTerminalPtNodePos, prevWordsNodePos, sizeof(mPrevWordsTerminalPtNodePos));
+        prevWordIds.copyToArray(&mPrevWordIds, 0 /* offset */);
+        mPrevWordCount = prevWordIds.size();
     }
 
     // Init for root with prevWordsPtNodePos which is used for n-gram
-    void init(const int rootPtNodeArrayPos, const int *const prevWordsNodePos) {
-        mPtNodePos = NOT_A_DICT_POS;
+    void init(const int rootPtNodeArrayPos, const WordIdArrayView prevWordIds) {
         mChildrenPtNodeArrayPos = rootPtNodeArrayPos;
         mDicNodeCodePoint = NOT_A_CODE_POINT;
-        mProbability = NOT_A_PROBABILITY;
-        mIsTerminal = false;
-        mHasChildrenPtNodes = true;
-        mIsBlacklistedOrNotAWord = false;
+        mWordId = NOT_A_WORD_ID;
         mDepth = 0;
         mLeavingDepth = 0;
-        memmove(mPrevWordsTerminalPtNodePos, prevWordsNodePos, sizeof(mPrevWordsTerminalPtNodePos));
+        prevWordIds.copyToArray(&mPrevWordIds, 0 /* offset */);
+        mPrevWordCount = prevWordIds.size();
     }
 
     void initByCopy(const DicNodeProperties *const dicNodeProp) {
-        mPtNodePos = dicNodeProp->mPtNodePos;
         mChildrenPtNodeArrayPos = dicNodeProp->mChildrenPtNodeArrayPos;
         mDicNodeCodePoint = dicNodeProp->mDicNodeCodePoint;
-        mProbability = dicNodeProp->mProbability;
-        mIsTerminal = dicNodeProp->mIsTerminal;
-        mHasChildrenPtNodes = dicNodeProp->mHasChildrenPtNodes;
-        mIsBlacklistedOrNotAWord = dicNodeProp->mIsBlacklistedOrNotAWord;
+        mWordId = dicNodeProp->mWordId;
         mDepth = dicNodeProp->mDepth;
         mLeavingDepth = dicNodeProp->mLeavingDepth;
-        memmove(mPrevWordsTerminalPtNodePos, dicNodeProp->mPrevWordsTerminalPtNodePos,
-                sizeof(mPrevWordsTerminalPtNodePos));
+        const WordIdArrayView prevWordIdArrayView = dicNodeProp->getPrevWordIds();
+        prevWordIdArrayView.copyToArray(&mPrevWordIds, 0 /* offset */);
+        mPrevWordCount = prevWordIdArrayView.size();
     }
 
     // Init as passing child
     void init(const DicNodeProperties *const dicNodeProp, const int codePoint) {
-        mPtNodePos = dicNodeProp->mPtNodePos;
         mChildrenPtNodeArrayPos = dicNodeProp->mChildrenPtNodeArrayPos;
         mDicNodeCodePoint = codePoint; // Overwrite the node char of a passing child
-        mProbability = dicNodeProp->mProbability;
-        mIsTerminal = dicNodeProp->mIsTerminal;
-        mHasChildrenPtNodes = dicNodeProp->mHasChildrenPtNodes;
-        mIsBlacklistedOrNotAWord = dicNodeProp->mIsBlacklistedOrNotAWord;
+        mWordId = dicNodeProp->mWordId;
         mDepth = dicNodeProp->mDepth + 1; // Increment the depth of a passing child
         mLeavingDepth = dicNodeProp->mLeavingDepth;
-        memmove(mPrevWordsTerminalPtNodePos, dicNodeProp->mPrevWordsTerminalPtNodePos,
-                sizeof(mPrevWordsTerminalPtNodePos));
-    }
-
-    int getPtNodePos() const {
-        return mPtNodePos;
+        const WordIdArrayView prevWordIdArrayView = dicNodeProp->getPrevWordIds();
+        prevWordIdArrayView.copyToArray(&mPrevWordIds, 0 /* offset */);
+        mPrevWordCount = prevWordIdArrayView.size();
     }
 
     int getChildrenPtNodeArrayPos() const {
         return mChildrenPtNodeArrayPos;
     }
 
-    int getProbability() const {
-        return mProbability;
-    }
-
     int getDicNodeCodePoint() const {
         return mDicNodeCodePoint;
     }
@@ -121,35 +100,32 @@ class DicNodeProperties {
     }
 
     bool isTerminal() const {
-        return mIsTerminal;
+        return mWordId != NOT_A_WORD_ID;
     }
 
     bool hasChildren() const {
-        return mHasChildrenPtNodes || mDepth != mLeavingDepth;
+        return (mChildrenPtNodeArrayPos != NOT_A_DICT_POS) || mDepth != mLeavingDepth;
     }
 
-    bool isBlacklistedOrNotAWord() const {
-        return mIsBlacklistedOrNotAWord;
+    const WordIdArrayView getPrevWordIds() const {
+        return WordIdArrayView::fromArray(mPrevWordIds).limit(mPrevWordCount);
     }
 
-    const int *getPrevWordsTerminalPtNodePos() const {
-        return mPrevWordsTerminalPtNodePos;
+    int getWordId() const {
+        return mWordId;
     }
 
  private:
     // Caution!!!
     // Use a default copy constructor and an assign operator because shallow copies are ok
     // for this class
-    int mPtNodePos;
     int mChildrenPtNodeArrayPos;
-    int mProbability;
     int mDicNodeCodePoint;
-    bool mIsTerminal;
-    bool mHasChildrenPtNodes;
-    bool mIsBlacklistedOrNotAWord;
+    int mWordId;
     uint16_t mDepth;
     uint16_t mLeavingDepth;
-    int mPrevWordsTerminalPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> mPrevWordIds;
+    size_t mPrevWordCount;
 };
 } // namespace latinime
 #endif // LATINIME_DIC_NODE_PROPERTIES_H
diff --git a/native/jni/src/suggest/core/dicnode/internal/dic_node_state_scoring.h b/native/jni/src/suggest/core/dicnode/internal/dic_node_state_scoring.h
index c19d48eb9..3a54c2599 100644
--- a/native/jni/src/suggest/core/dicnode/internal/dic_node_state_scoring.h
+++ b/native/jni/src/suggest/core/dicnode/internal/dic_node_state_scoring.h
@@ -103,8 +103,10 @@ class DicNodeStateScoring {
         return getCompoundDistance(1.0f);
     }
 
-    float getCompoundDistance(const float languageWeight) const {
-        return mSpatialDistance + mLanguageDistance * languageWeight;
+    float getCompoundDistance(
+            const float weightOfLangModelVsSpatialModel) const {
+        return mSpatialDistance
+                + mLanguageDistance * weightOfLangModelVsSpatialModel;
     }
 
     float getNormalizedCompoundDistance() const {
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.cpp b/native/jni/src/suggest/core/dictionary/dictionary.cpp
index d62573970..5c9a1392e 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.cpp
+++ b/native/jni/src/suggest/core/dictionary/dictionary.cpp
@@ -19,15 +19,16 @@
 #include "suggest/core/dictionary/dictionary.h"
 
 #include "defines.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/property/ngram_context.h"
 #include "suggest/core/dictionary/dictionary_utils.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
 #include "suggest/core/result/suggestion_results.h"
 #include "suggest/core/session/dic_traverse_session.h"
-#include "suggest/core/session/prev_words_info.h"
 #include "suggest/core/suggest.h"
 #include "suggest/core/suggest_options.h"
 #include "suggest/policyimpl/gesture/gesture_suggest_policy_factory.h"
 #include "suggest/policyimpl/typing/typing_suggest_policy_factory.h"
+#include "utils/int_array_view.h"
 #include "utils/log_utils.h"
 #include "utils/time_keeper.h"
 
@@ -45,88 +46,87 @@ Dictionary::Dictionary(JNIEnv *env, DictionaryStructureWithBufferPolicy::Structu
 
 void Dictionary::getSuggestions(ProximityInfo *proximityInfo, DicTraverseSession *traverseSession,
         int *xcoordinates, int *ycoordinates, int *times, int *pointerIds, int *inputCodePoints,
-        int inputSize, const PrevWordsInfo *const prevWordsInfo,
-        const SuggestOptions *const suggestOptions, const float languageWeight,
+        int inputSize, const NgramContext *const ngramContext,
+        const SuggestOptions *const suggestOptions, const float weightOfLangModelVsSpatialModel,
         SuggestionResults *const outSuggestionResults) const {
     TimeKeeper::setCurrentTime();
-    traverseSession->init(this, prevWordsInfo, suggestOptions);
+    traverseSession->init(this, ngramContext, suggestOptions);
     const auto &suggest = suggestOptions->isGesture() ? mGestureSuggest : mTypingSuggest;
     suggest->getSuggestions(proximityInfo, traverseSession, xcoordinates,
             ycoordinates, times, pointerIds, inputCodePoints, inputSize,
-            languageWeight, outSuggestionResults);
-    if (DEBUG_DICT) {
-        outSuggestionResults->dumpSuggestions();
-    }
+            weightOfLangModelVsSpatialModel, outSuggestionResults);
 }
 
 Dictionary::NgramListenerForPrediction::NgramListenerForPrediction(
-        const PrevWordsInfo *const prevWordsInfo, SuggestionResults *const suggestionResults,
+        const NgramContext *const ngramContext, const WordIdArrayView prevWordIds,
+        SuggestionResults *const suggestionResults,
         const DictionaryStructureWithBufferPolicy *const dictStructurePolicy)
-    : mPrevWordsInfo(prevWordsInfo), mSuggestionResults(suggestionResults),
-      mDictStructurePolicy(dictStructurePolicy) {}
+    : mNgramContext(ngramContext), mPrevWordIds(prevWordIds),
+      mSuggestionResults(suggestionResults), mDictStructurePolicy(dictStructurePolicy) {}
 
 void Dictionary::NgramListenerForPrediction::onVisitEntry(const int ngramProbability,
-        const int targetPtNodePos) {
-    if (targetPtNodePos == NOT_A_DICT_POS) {
+        const int targetWordId) {
+    if (targetWordId == NOT_A_WORD_ID) {
         return;
     }
-    if (mPrevWordsInfo->isNthPrevWordBeginningOfSentence(1 /* n */)
+    if (mNgramContext->isNthPrevWordBeginningOfSentence(1 /* n */)
             && ngramProbability == NOT_A_PROBABILITY) {
         return;
     }
     int targetWordCodePoints[MAX_WORD_LENGTH];
-    int unigramProbability = 0;
-    const int codePointCount = mDictStructurePolicy->
-            getCodePointsAndProbabilityAndReturnCodePointCount(targetPtNodePos,
-                    MAX_WORD_LENGTH, targetWordCodePoints, &unigramProbability);
+    const int codePointCount = mDictStructurePolicy->getCodePointsAndReturnCodePointCount(
+            targetWordId, MAX_WORD_LENGTH, targetWordCodePoints);
     if (codePointCount <= 0) {
         return;
     }
-    const int probability = mDictStructurePolicy->getProbability(
-            unigramProbability, ngramProbability);
-    mSuggestionResults->addPrediction(targetWordCodePoints, codePointCount, probability);
+    const WordAttributes wordAttributes = mDictStructurePolicy->getWordAttributesInContext(
+            mPrevWordIds, targetWordId, nullptr /* multiBigramMap */);
+    if (wordAttributes.getProbability() == NOT_A_PROBABILITY) {
+        return;
+    }
+    mSuggestionResults->addPrediction(targetWordCodePoints, codePointCount,
+            wordAttributes.getProbability());
 }
 
-void Dictionary::getPredictions(const PrevWordsInfo *const prevWordsInfo,
+void Dictionary::getPredictions(const NgramContext *const ngramContext,
         SuggestionResults *const outSuggestionResults) const {
     TimeKeeper::setCurrentTime();
-    NgramListenerForPrediction listener(prevWordsInfo, outSuggestionResults,
-            mDictionaryStructureWithBufferPolicy.get());
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(
-            mDictionaryStructureWithBufferPolicy.get(), prevWordsPtNodePos,
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(
+            mDictionaryStructureWithBufferPolicy.get(), &prevWordIdArray,
             true /* tryLowerCaseSearch */);
-    mDictionaryStructureWithBufferPolicy->iterateNgramEntries(prevWordsPtNodePos, &listener);
+    NgramListenerForPrediction listener(ngramContext, prevWordIds, outSuggestionResults,
+            mDictionaryStructureWithBufferPolicy.get());
+    mDictionaryStructureWithBufferPolicy->iterateNgramEntries(prevWordIds, &listener);
 }
 
-int Dictionary::getProbability(const int *word, int length) const {
-    return getNgramProbability(nullptr /* prevWordsInfo */, word, length);
+int Dictionary::getProbability(const CodePointArrayView codePoints) const {
+    return getNgramProbability(nullptr /* ngramContext */, codePoints);
 }
 
-int Dictionary::getMaxProbabilityOfExactMatches(const int *word, int length) const {
+int Dictionary::getMaxProbabilityOfExactMatches(const CodePointArrayView codePoints) const {
     TimeKeeper::setCurrentTime();
     return DictionaryUtils::getMaxProbabilityOfExactMatches(
-            mDictionaryStructureWithBufferPolicy.get(), word, length);
+            mDictionaryStructureWithBufferPolicy.get(), codePoints);
 }
 
-int Dictionary::getNgramProbability(const PrevWordsInfo *const prevWordsInfo, const int *word,
-        int length) const {
+int Dictionary::getNgramProbability(const NgramContext *const ngramContext,
+        const CodePointArrayView codePoints) const {
     TimeKeeper::setCurrentTime();
-    int nextWordPos = mDictionaryStructureWithBufferPolicy->getTerminalPtNodePositionOfWord(word,
-            length, false /* forceLowerCaseSearch */);
-    if (NOT_A_DICT_POS == nextWordPos) return NOT_A_PROBABILITY;
-    if (!prevWordsInfo) {
-        return getDictionaryStructurePolicy()->getProbabilityOfPtNode(
-                nullptr /* prevWordsPtNodePos */, nextWordPos);
+    const int wordId = mDictionaryStructureWithBufferPolicy->getWordId(codePoints,
+            false /* forceLowerCaseSearch */);
+    if (wordId == NOT_A_WORD_ID) return NOT_A_PROBABILITY;
+    if (!ngramContext) {
+        return getDictionaryStructurePolicy()->getProbabilityOfWord(WordIdArrayView(), wordId);
     }
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(
-            mDictionaryStructureWithBufferPolicy.get(), prevWordsPtNodePos,
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = ngramContext->getPrevWordIds(
+            mDictionaryStructureWithBufferPolicy.get(), &prevWordIdArray,
             true /* tryLowerCaseSearch */);
-    return getDictionaryStructurePolicy()->getProbabilityOfPtNode(prevWordsPtNodePos, nextWordPos);
+    return getDictionaryStructurePolicy()->getProbabilityOfWord(prevWordIds, wordId);
 }
 
-bool Dictionary::addUnigramEntry(const int *const word, const int length,
+bool Dictionary::addUnigramEntry(const CodePointArrayView codePoints,
         const UnigramProperty *const unigramProperty) {
     if (unigramProperty->representsBeginningOfSentence()
             && !mDictionaryStructureWithBufferPolicy->getHeaderStructurePolicy()
@@ -135,24 +135,31 @@ bool Dictionary::addUnigramEntry(const int *const word, const int length,
         return false;
     }
     TimeKeeper::setCurrentTime();
-    return mDictionaryStructureWithBufferPolicy->addUnigramEntry(word, length, unigramProperty);
+    return mDictionaryStructureWithBufferPolicy->addUnigramEntry(codePoints, unigramProperty);
+}
+
+bool Dictionary::removeUnigramEntry(const CodePointArrayView codePoints) {
+    TimeKeeper::setCurrentTime();
+    return mDictionaryStructureWithBufferPolicy->removeUnigramEntry(codePoints);
 }
 
-bool Dictionary::removeUnigramEntry(const int *const codePoints, const int codePointCount) {
+bool Dictionary::addNgramEntry(const NgramProperty *const ngramProperty) {
     TimeKeeper::setCurrentTime();
-    return mDictionaryStructureWithBufferPolicy->removeUnigramEntry(codePoints, codePointCount);
+    return mDictionaryStructureWithBufferPolicy->addNgramEntry(ngramProperty);
 }
 
-bool Dictionary::addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const BigramProperty *const bigramProperty) {
+bool Dictionary::removeNgramEntry(const NgramContext *const ngramContext,
+        const CodePointArrayView codePoints) {
     TimeKeeper::setCurrentTime();
-    return mDictionaryStructureWithBufferPolicy->addNgramEntry(prevWordsInfo, bigramProperty);
+    return mDictionaryStructureWithBufferPolicy->removeNgramEntry(ngramContext, codePoints);
 }
 
-bool Dictionary::removeNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const int *const word, const int length) {
+bool Dictionary::updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+        const CodePointArrayView codePoints, const bool isValidWord,
+        const HistoricalInfo historicalInfo) {
     TimeKeeper::setCurrentTime();
-    return mDictionaryStructureWithBufferPolicy->removeNgramEntry(prevWordsInfo, word, length);
+    return mDictionaryStructureWithBufferPolicy->updateEntriesForWordWithNgramContext(ngramContext,
+            codePoints, isValidWord, historicalInfo);
 }
 
 bool Dictionary::flush(const char *const filePath) {
@@ -177,11 +184,9 @@ void Dictionary::getProperty(const char *const query, const int queryLength, cha
             maxResultLength);
 }
 
-const WordProperty Dictionary::getWordProperty(const int *const codePoints,
-        const int codePointCount) {
+const WordProperty Dictionary::getWordProperty(const CodePointArrayView codePoints) {
     TimeKeeper::setCurrentTime();
-    return mDictionaryStructureWithBufferPolicy->getWordProperty(
-            codePoints, codePointCount);
+    return mDictionaryStructureWithBufferPolicy->getWordProperty(codePoints);
 }
 
 int Dictionary::getNextWordAndNextToken(const int token, int *const outCodePoints,
diff --git a/native/jni/src/suggest/core/dictionary/dictionary.h b/native/jni/src/suggest/core/dictionary/dictionary.h
index 732d3b199..9e224ebfb 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary.h
+++ b/native/jni/src/suggest/core/dictionary/dictionary.h
@@ -21,17 +21,19 @@
 
 #include "defines.h"
 #include "jni.h"
-#include "suggest/core/dictionary/ngram_listener.h"
-#include "suggest/core/dictionary/property/word_property.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/interface/ngram_listener.h"
+#include "dictionary/property/historical_info.h"
+#include "dictionary/property/word_property.h"
 #include "suggest/core/suggest_interface.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 class DictionaryStructureWithBufferPolicy;
 class DicTraverseSession;
-class PrevWordsInfo;
+class NgramContext;
 class ProximityInfo;
 class SuggestionResults;
 class SuggestOptions;
@@ -58,36 +60,40 @@ class Dictionary {
     static const int KIND_FLAG_POSSIBLY_OFFENSIVE = 0x80000000;
     static const int KIND_FLAG_EXACT_MATCH = 0x40000000;
     static const int KIND_FLAG_EXACT_MATCH_WITH_INTENTIONAL_OMISSION = 0x20000000;
+    static const int KIND_FLAG_APPROPRIATE_FOR_AUTOCORRECTION = 0x10000000;
 
     Dictionary(JNIEnv *env, DictionaryStructureWithBufferPolicy::StructurePolicyPtr
             dictionaryStructureWithBufferPolicy);
 
     void getSuggestions(ProximityInfo *proximityInfo, DicTraverseSession *traverseSession,
             int *xcoordinates, int *ycoordinates, int *times, int *pointerIds, int *inputCodePoints,
-            int inputSize, const PrevWordsInfo *const prevWordsInfo,
-            const SuggestOptions *const suggestOptions, const float languageWeight,
+            int inputSize, const NgramContext *const ngramContext,
+            const SuggestOptions *const suggestOptions, const float weightOfLangModelVsSpatialModel,
             SuggestionResults *const outSuggestionResults) const;
 
-    void getPredictions(const PrevWordsInfo *const prevWordsInfo,
+    void getPredictions(const NgramContext *const ngramContext,
             SuggestionResults *const outSuggestionResults) const;
 
-    int getProbability(const int *word, int length) const;
+    int getProbability(const CodePointArrayView codePoints) const;
 
-    int getMaxProbabilityOfExactMatches(const int *word, int length) const;
+    int getMaxProbabilityOfExactMatches(const CodePointArrayView codePoints) const;
 
-    int getNgramProbability(const PrevWordsInfo *const prevWordsInfo,
-            const int *word, int length) const;
+    int getNgramProbability(const NgramContext *const ngramContext,
+            const CodePointArrayView codePoints) const;
 
-    bool addUnigramEntry(const int *const codePoints, const int codePointCount,
+    bool addUnigramEntry(const CodePointArrayView codePoints,
             const UnigramProperty *const unigramProperty);
 
-    bool removeUnigramEntry(const int *const codePoints, const int codePointCount);
+    bool removeUnigramEntry(const CodePointArrayView codePoints);
 
-    bool addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-            const BigramProperty *const bigramProperty);
+    bool addNgramEntry(const NgramProperty *const ngramProperty);
 
-    bool removeNgramEntry(const PrevWordsInfo *const prevWordsInfo, const int *const word,
-            const int length);
+    bool removeNgramEntry(const NgramContext *const ngramContext,
+            const CodePointArrayView codePoints);
+
+    bool updateEntriesForWordWithNgramContext(const NgramContext *const ngramContext,
+            const CodePointArrayView codePoints, const bool isValidWord,
+            const HistoricalInfo historicalInfo);
 
     bool flush(const char *const filePath);
 
@@ -98,7 +104,7 @@ class Dictionary {
     void getProperty(const char *const query, const int queryLength, char *const outResult,
             const int maxResultLength);
 
-    const WordProperty getWordProperty(const int *const codePoints, const int codePointCount);
+    const WordProperty getWordProperty(const CodePointArrayView codePoints);
 
     // Method to iterate all words in the dictionary.
     // The returned token has to be used to get the next word. If token is 0, this method newly
@@ -117,15 +123,16 @@ class Dictionary {
 
     class NgramListenerForPrediction : public NgramListener {
      public:
-        NgramListenerForPrediction(const PrevWordsInfo *const prevWordsInfo,
-                SuggestionResults *const suggestionResults,
+        NgramListenerForPrediction(const NgramContext *const ngramContext,
+                const WordIdArrayView prevWordIds, SuggestionResults *const suggestionResults,
                 const DictionaryStructureWithBufferPolicy *const dictStructurePolicy);
-        virtual void onVisitEntry(const int ngramProbability, const int targetPtNodePos);
+        virtual void onVisitEntry(const int ngramProbability, const int targetWordId);
 
      private:
         DISALLOW_IMPLICIT_CONSTRUCTORS(NgramListenerForPrediction);
 
-        const PrevWordsInfo *const mPrevWordsInfo;
+        const NgramContext *const mNgramContext;
+        const WordIdArrayView mPrevWordIds;
         SuggestionResults *const mSuggestionResults;
         const DictionaryStructureWithBufferPolicy *const mDictStructurePolicy;
     };
diff --git a/native/jni/src/suggest/core/dictionary/dictionary_utils.cpp b/native/jni/src/suggest/core/dictionary/dictionary_utils.cpp
index b94966cbe..7de550026 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary_utils.cpp
+++ b/native/jni/src/suggest/core/dictionary/dictionary_utils.cpp
@@ -16,39 +16,40 @@
 
 #include "suggest/core/dictionary/dictionary_utils.h"
 
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/property/ngram_context.h"
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_priority_queue.h"
 #include "suggest/core/dicnode/dic_node_vector.h"
 #include "suggest/core/dictionary/dictionary.h"
 #include "suggest/core/dictionary/digraph_utils.h"
-#include "suggest/core/session/prev_words_info.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 /* static */ int DictionaryUtils::getMaxProbabilityOfExactMatches(
         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-        const int *const codePoints, const int codePointCount) {
+        const CodePointArrayView codePoints) {
     std::vector<DicNode> current;
     std::vector<DicNode> next;
 
-    // No prev words information.
-    PrevWordsInfo emptyPrevWordsInfo;
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    emptyPrevWordsInfo.getPrevWordsTerminalPtNodePos(dictionaryStructurePolicy,
-            prevWordsPtNodePos, false /* tryLowerCaseSearch */);
+    // No ngram context.
+    NgramContext emptyNgramContext;
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> prevWordIdArray;
+    const WordIdArrayView prevWordIds = emptyNgramContext.getPrevWordIds(
+            dictionaryStructurePolicy, &prevWordIdArray, false /* tryLowerCaseSearch */);
     current.emplace_back();
-    DicNodeUtils::initAsRoot(dictionaryStructurePolicy, prevWordsPtNodePos, &current.front());
-    for (int i = 0; i < codePointCount; ++i) {
+    DicNodeUtils::initAsRoot(dictionaryStructurePolicy, prevWordIds, &current.front());
+    for (const int codePoint : codePoints) {
         // The base-lower input is used to ignore case errors and accent errors.
-        const int codePoint = CharUtils::toBaseLowerCase(codePoints[i]);
+        const int baseLowerCodePoint = CharUtils::toBaseLowerCase(codePoint);
         for (const DicNode &dicNode : current) {
-            if (dicNode.isInDigraph() && dicNode.getNodeCodePoint() == codePoint) {
+            if (dicNode.isInDigraph() && dicNode.getNodeCodePoint() == baseLowerCodePoint) {
                 next.emplace_back(dicNode);
                 next.back().advanceDigraphIndex();
                 continue;
             }
-            processChildDicNodes(dictionaryStructurePolicy, codePoint, &dicNode, &next);
+            processChildDicNodes(dictionaryStructurePolicy, baseLowerCodePoint, &dicNode, &next);
         }
         current.clear();
         current.swap(next);
@@ -59,8 +60,11 @@ namespace latinime {
         if (!dicNode.isTerminalDicNode()) {
             continue;
         }
+        const WordAttributes wordAttributes =
+                dictionaryStructurePolicy->getWordAttributesInContext(dicNode.getPrevWordIds(),
+                        dicNode.getWordId(), nullptr /* multiBigramMap */);
         // dicNode can contain case errors, accent errors, intentional omissions or digraphs.
-        maxProbability = std::max(maxProbability, dicNode.getProbability());
+        maxProbability = std::max(maxProbability, wordAttributes.getProbability());
     }
     return maxProbability;
 }
diff --git a/native/jni/src/suggest/core/dictionary/dictionary_utils.h b/native/jni/src/suggest/core/dictionary/dictionary_utils.h
index 358ebf674..4dd21c9be 100644
--- a/native/jni/src/suggest/core/dictionary/dictionary_utils.h
+++ b/native/jni/src/suggest/core/dictionary/dictionary_utils.h
@@ -20,6 +20,7 @@
 #include <vector>
 
 #include "defines.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
@@ -30,7 +31,7 @@ class DictionaryUtils {
  public:
     static int getMaxProbabilityOfExactMatches(
             const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
-            const int *const codePoints, const int codePointCount);
+            const CodePointArrayView codePoints);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DictionaryUtils);
diff --git a/native/jni/src/suggest/core/dictionary/digraph_utils.cpp b/native/jni/src/suggest/core/dictionary/digraph_utils.cpp
index bb2ce5012..4d68f620f 100644
--- a/native/jni/src/suggest/core/dictionary/digraph_utils.cpp
+++ b/native/jni/src/suggest/core/dictionary/digraph_utils.cpp
@@ -19,7 +19,7 @@
 #include <cstdlib>
 
 #include "defines.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
 #include "utils/char_utils.h"
 
 namespace latinime {
diff --git a/native/jni/src/suggest/core/dictionary/error_type_utils.cpp b/native/jni/src/suggest/core/dictionary/error_type_utils.cpp
index b6bf7a98c..61093e174 100644
--- a/native/jni/src/suggest/core/dictionary/error_type_utils.cpp
+++ b/native/jni/src/suggest/core/dictionary/error_type_utils.cpp
@@ -19,17 +19,20 @@
 namespace latinime {
 
 const ErrorTypeUtils::ErrorType ErrorTypeUtils::NOT_AN_ERROR = 0x0;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_CASE_ERROR = 0x1;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_ACCENT_ERROR = 0x2;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_DIGRAPH = 0x4;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::INTENTIONAL_OMISSION = 0x8;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::EDIT_CORRECTION = 0x10;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::PROXIMITY_CORRECTION = 0x20;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::COMPLETION = 0x40;
-const ErrorTypeUtils::ErrorType ErrorTypeUtils::NEW_WORD = 0x80;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_WRONG_CASE = 0x1;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_MISSING_ACCENT = 0x2;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_MISSING_EXPLICIT_ACCENT = 0x4;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_WRONG_ACCENT = 0x8;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::MATCH_WITH_DIGRAPH = 0x10;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::INTENTIONAL_OMISSION = 0x20;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::EDIT_CORRECTION = 0x40;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::PROXIMITY_CORRECTION = 0x80;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::COMPLETION = 0x100;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::NEW_WORD = 0x200;
 
 const ErrorTypeUtils::ErrorType ErrorTypeUtils::ERRORS_TREATED_AS_AN_EXACT_MATCH =
-        NOT_AN_ERROR | MATCH_WITH_CASE_ERROR | MATCH_WITH_ACCENT_ERROR | MATCH_WITH_DIGRAPH;
+        NOT_AN_ERROR | MATCH_WITH_WRONG_CASE | MATCH_WITH_MISSING_ACCENT | MATCH_WITH_DIGRAPH;
+const ErrorTypeUtils::ErrorType ErrorTypeUtils::ERRORS_TREATED_AS_A_PERFECT_MATCH = NOT_AN_ERROR;
 
 const ErrorTypeUtils::ErrorType
         ErrorTypeUtils::ERRORS_TREATED_AS_AN_EXACT_MATCH_WITH_INTENTIONAL_OMISSION =
diff --git a/native/jni/src/suggest/core/dictionary/error_type_utils.h b/native/jni/src/suggest/core/dictionary/error_type_utils.h
index e3e76b238..75111ba75 100644
--- a/native/jni/src/suggest/core/dictionary/error_type_utils.h
+++ b/native/jni/src/suggest/core/dictionary/error_type_utils.h
@@ -30,8 +30,10 @@ class ErrorTypeUtils {
     typedef uint32_t ErrorType;
 
     static const ErrorType NOT_AN_ERROR;
-    static const ErrorType MATCH_WITH_CASE_ERROR;
-    static const ErrorType MATCH_WITH_ACCENT_ERROR;
+    static const ErrorType MATCH_WITH_WRONG_CASE;
+    static const ErrorType MATCH_WITH_MISSING_ACCENT;
+    static const ErrorType MATCH_WITH_MISSING_EXPLICIT_ACCENT;
+    static const ErrorType MATCH_WITH_WRONG_ACCENT;
     static const ErrorType MATCH_WITH_DIGRAPH;
     // Treat error as an intentional omission when the CorrectionType is omission and the node can
     // be intentional omission.
@@ -51,11 +53,19 @@ class ErrorTypeUtils {
         return (containedErrorTypes & ~ERRORS_TREATED_AS_AN_EXACT_MATCH) == 0;
     }
 
+    static bool isPerfectMatch(const ErrorType containedErrorTypes) {
+        return (containedErrorTypes & ~ERRORS_TREATED_AS_A_PERFECT_MATCH) == 0;
+    }
+
     static bool isExactMatchWithIntentionalOmission(const ErrorType containedErrorTypes) {
         return (containedErrorTypes
                 & ~ERRORS_TREATED_AS_AN_EXACT_MATCH_WITH_INTENTIONAL_OMISSION) == 0;
     }
 
+    static bool isMissingExplicitAccent(const ErrorType errorType) {
+        return (errorType & MATCH_WITH_MISSING_EXPLICIT_ACCENT) != 0;
+    }
+
     static bool isEditCorrectionError(const ErrorType errorType) {
         return (errorType & EDIT_CORRECTION) != 0;
     }
@@ -72,6 +82,7 @@ class ErrorTypeUtils {
     DISALLOW_IMPLICIT_CONSTRUCTORS(ErrorTypeUtils);
 
     static const ErrorType ERRORS_TREATED_AS_AN_EXACT_MATCH;
+    static const ErrorType ERRORS_TREATED_AS_A_PERFECT_MATCH;
     static const ErrorType ERRORS_TREATED_AS_AN_EXACT_MATCH_WITH_INTENTIONAL_OMISSION;
 };
 } // namespace latinime
diff --git a/native/jni/src/suggest/core/dictionary/property/bigram_property.h b/native/jni/src/suggest/core/dictionary/property/bigram_property.h
deleted file mode 100644
index 343af143c..000000000
--- a/native/jni/src/suggest/core/dictionary/property/bigram_property.h
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_BIGRAM_PROPERTY_H
-#define LATINIME_BIGRAM_PROPERTY_H
-
-#include <vector>
-
-#include "defines.h"
-
-namespace latinime {
-
-// TODO: Change to NgramProperty.
-class BigramProperty {
- public:
-    BigramProperty(const std::vector<int> *const targetCodePoints,
-            const int probability, const int timestamp, const int level, const int count)
-            : mTargetCodePoints(*targetCodePoints), mProbability(probability),
-              mTimestamp(timestamp), mLevel(level), mCount(count) {}
-
-    const std::vector<int> *getTargetCodePoints() const {
-        return &mTargetCodePoints;
-    }
-
-    int getProbability() const {
-        return mProbability;
-    }
-
-    int getTimestamp() const {
-        return mTimestamp;
-    }
-
-    int getLevel() const {
-        return mLevel;
-    }
-
-    int getCount() const {
-        return mCount;
-    }
-
- private:
-    // Default copy constructor and assign operator are used for using in std::vector.
-    DISALLOW_DEFAULT_CONSTRUCTOR(BigramProperty);
-
-    // TODO: Make members const.
-    std::vector<int> mTargetCodePoints;
-    int mProbability;
-    int mTimestamp;
-    int mLevel;
-    int mCount;
-};
-} // namespace latinime
-#endif // LATINIME_WORD_PROPERTY_H
diff --git a/native/jni/src/suggest/core/dictionary/property/unigram_property.h b/native/jni/src/suggest/core/dictionary/property/unigram_property.h
deleted file mode 100644
index 902eb000f..000000000
--- a/native/jni/src/suggest/core/dictionary/property/unigram_property.h
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_UNIGRAM_PROPERTY_H
-#define LATINIME_UNIGRAM_PROPERTY_H
-
-#include <vector>
-
-#include "defines.h"
-
-namespace latinime {
-
-class UnigramProperty {
- public:
-    class ShortcutProperty {
-     public:
-        ShortcutProperty(const std::vector<int> *const targetCodePoints, const int probability)
-                : mTargetCodePoints(*targetCodePoints), mProbability(probability) {}
-
-        const std::vector<int> *getTargetCodePoints() const {
-            return &mTargetCodePoints;
-        }
-
-        int getProbability() const {
-            return mProbability;
-        }
-
-     private:
-        // Default copy constructor and assign operator are used for using in std::vector.
-        DISALLOW_DEFAULT_CONSTRUCTOR(ShortcutProperty);
-
-        // TODO: Make members const.
-        std::vector<int> mTargetCodePoints;
-        int mProbability;
-    };
-
-    UnigramProperty()
-            : mRepresentsBeginningOfSentence(false), mIsNotAWord(false), mIsBlacklisted(false),
-              mProbability(NOT_A_PROBABILITY), mTimestamp(NOT_A_TIMESTAMP), mLevel(0), mCount(0),
-              mShortcuts() {}
-
-    UnigramProperty(const bool representsBeginningOfSentence, const bool isNotAWord,
-            const bool isBlacklisted, const int probability, const int timestamp, const int level,
-            const int count, const std::vector<ShortcutProperty> *const shortcuts)
-            : mRepresentsBeginningOfSentence(representsBeginningOfSentence),
-              mIsNotAWord(isNotAWord), mIsBlacklisted(isBlacklisted), mProbability(probability),
-              mTimestamp(timestamp), mLevel(level), mCount(count), mShortcuts(*shortcuts) {}
-
-    bool representsBeginningOfSentence() const {
-        return mRepresentsBeginningOfSentence;
-    }
-
-    bool isNotAWord() const {
-        return mIsNotAWord;
-    }
-
-    bool isBlacklisted() const {
-        return mIsBlacklisted;
-    }
-
-    bool hasShortcuts() const {
-        return !mShortcuts.empty();
-    }
-
-    int getProbability() const {
-        return mProbability;
-    }
-
-    int getTimestamp() const {
-        return mTimestamp;
-    }
-
-    int getLevel() const {
-        return mLevel;
-    }
-
-    int getCount() const {
-        return mCount;
-    }
-
-    const std::vector<ShortcutProperty> &getShortcuts() const {
-        return mShortcuts;
-    }
-
- private:
-    // Default copy constructor is used for using as a return value.
-    DISALLOW_ASSIGNMENT_OPERATOR(UnigramProperty);
-
-    // TODO: Make members const.
-    bool mRepresentsBeginningOfSentence;
-    bool mIsNotAWord;
-    bool mIsBlacklisted;
-    int mProbability;
-    // Historical information
-    int mTimestamp;
-    int mLevel;
-    int mCount;
-    std::vector<ShortcutProperty> mShortcuts;
-};
-} // namespace latinime
-#endif // LATINIME_UNIGRAM_PROPERTY_H
diff --git a/native/jni/src/suggest/core/dictionary/property/word_property.cpp b/native/jni/src/suggest/core/dictionary/property/word_property.cpp
deleted file mode 100644
index 5bdd5606b..000000000
--- a/native/jni/src/suggest/core/dictionary/property/word_property.cpp
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/core/dictionary/property/word_property.h"
-
-#include "utils/jni_data_utils.h"
-
-namespace latinime {
-
-void WordProperty::outputProperties(JNIEnv *const env, jintArray outCodePoints,
-        jbooleanArray outFlags, jintArray outProbabilityInfo, jobject outBigramTargets,
-        jobject outBigramProbabilities, jobject outShortcutTargets,
-        jobject outShortcutProbabilities) const {
-    JniDataUtils::outputCodePoints(env, outCodePoints, 0 /* start */,
-            MAX_WORD_LENGTH /* maxLength */, mCodePoints.data(), mCodePoints.size(),
-            false /* needsNullTermination */);
-    jboolean flags[] = {mUnigramProperty.isNotAWord(), mUnigramProperty.isBlacklisted(),
-            !mBigrams.empty(), mUnigramProperty.hasShortcuts(),
-            mUnigramProperty.representsBeginningOfSentence()};
-    env->SetBooleanArrayRegion(outFlags, 0 /* start */, NELEMS(flags), flags);
-    int probabilityInfo[] = {mUnigramProperty.getProbability(), mUnigramProperty.getTimestamp(),
-            mUnigramProperty.getLevel(), mUnigramProperty.getCount()};
-    env->SetIntArrayRegion(outProbabilityInfo, 0 /* start */, NELEMS(probabilityInfo),
-            probabilityInfo);
-
-    jclass integerClass = env->FindClass("java/lang/Integer");
-    jmethodID intToIntegerConstructorId = env->GetMethodID(integerClass, "<init>", "(I)V");
-    jclass arrayListClass = env->FindClass("java/util/ArrayList");
-    jmethodID addMethodId = env->GetMethodID(arrayListClass, "add", "(Ljava/lang/Object;)Z");
-
-    // Output bigrams.
-    for (const auto &bigramProperty : mBigrams) {
-        const std::vector<int> *const word1CodePoints = bigramProperty.getTargetCodePoints();
-        jintArray bigramWord1CodePointArray = env->NewIntArray(word1CodePoints->size());
-        JniDataUtils::outputCodePoints(env, bigramWord1CodePointArray, 0 /* start */,
-                word1CodePoints->size(), word1CodePoints->data(), word1CodePoints->size(),
-                false /* needsNullTermination */);
-        env->CallBooleanMethod(outBigramTargets, addMethodId, bigramWord1CodePointArray);
-        env->DeleteLocalRef(bigramWord1CodePointArray);
-
-        int bigramProbabilityInfo[] = {bigramProperty.getProbability(),
-                bigramProperty.getTimestamp(), bigramProperty.getLevel(),
-                bigramProperty.getCount()};
-        jintArray bigramProbabilityInfoArray = env->NewIntArray(NELEMS(bigramProbabilityInfo));
-        env->SetIntArrayRegion(bigramProbabilityInfoArray, 0 /* start */,
-                NELEMS(bigramProbabilityInfo), bigramProbabilityInfo);
-        env->CallBooleanMethod(outBigramProbabilities, addMethodId, bigramProbabilityInfoArray);
-        env->DeleteLocalRef(bigramProbabilityInfoArray);
-    }
-
-    // Output shortcuts.
-    for (const auto &shortcut : mUnigramProperty.getShortcuts()) {
-        const std::vector<int> *const targetCodePoints = shortcut.getTargetCodePoints();
-        jintArray shortcutTargetCodePointArray = env->NewIntArray(targetCodePoints->size());
-        env->SetIntArrayRegion(shortcutTargetCodePointArray, 0 /* start */,
-                targetCodePoints->size(), targetCodePoints->data());
-        JniDataUtils::outputCodePoints(env, shortcutTargetCodePointArray, 0 /* start */,
-                targetCodePoints->size(), targetCodePoints->data(), targetCodePoints->size(),
-                false /* needsNullTermination */);
-        env->CallBooleanMethod(outShortcutTargets, addMethodId, shortcutTargetCodePointArray);
-        env->DeleteLocalRef(shortcutTargetCodePointArray);
-        jobject integerProbability = env->NewObject(integerClass, intToIntegerConstructorId,
-                shortcut.getProbability());
-        env->CallBooleanMethod(outShortcutProbabilities, addMethodId, integerProbability);
-        env->DeleteLocalRef(integerProbability);
-    }
-    env->DeleteLocalRef(integerClass);
-    env->DeleteLocalRef(arrayListClass);
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/core/layout/additional_proximity_chars.cpp b/native/jni/src/suggest/core/layout/additional_proximity_chars.cpp
index 34b8b37b0..8b39f7da5 100644
--- a/native/jni/src/suggest/core/layout/additional_proximity_chars.cpp
+++ b/native/jni/src/suggest/core/layout/additional_proximity_chars.cpp
@@ -19,7 +19,7 @@
 namespace latinime {
 // TODO: Stop using hardcoded additional proximity characters.
 // TODO: Have proximity character informations in each language's binary dictionary.
-const char *AdditionalProximityChars::LOCALE_EN_US = "en";
+const int AdditionalProximityChars::LOCALE_EN_US[LOCALE_EN_US_SIZE] = { 'e', 'n' };
 
 const int AdditionalProximityChars::EN_US_ADDITIONAL_A[EN_US_ADDITIONAL_A_SIZE] = {
     'e', 'i', 'o', 'u'
diff --git a/native/jni/src/suggest/core/layout/additional_proximity_chars.h b/native/jni/src/suggest/core/layout/additional_proximity_chars.h
index a88fd6cea..2260be9bd 100644
--- a/native/jni/src/suggest/core/layout/additional_proximity_chars.h
+++ b/native/jni/src/suggest/core/layout/additional_proximity_chars.h
@@ -18,6 +18,7 @@
 #define LATINIME_ADDITIONAL_PROXIMITY_CHARS_H
 
 #include <cstring>
+#include <vector>
 
 #include "defines.h"
 
@@ -26,7 +27,8 @@ namespace latinime {
 class AdditionalProximityChars {
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(AdditionalProximityChars);
-    static const char *LOCALE_EN_US;
+    static const int LOCALE_EN_US_SIZE = 2;
+    static const int LOCALE_EN_US[LOCALE_EN_US_SIZE];
     static const int EN_US_ADDITIONAL_A_SIZE = 4;
     static const int EN_US_ADDITIONAL_A[];
     static const int EN_US_ADDITIONAL_E_SIZE = 4;
@@ -38,15 +40,22 @@ class AdditionalProximityChars {
     static const int EN_US_ADDITIONAL_U_SIZE = 4;
     static const int EN_US_ADDITIONAL_U[];
 
-    AK_FORCE_INLINE static bool isEnLocale(const char *localeStr) {
-        const size_t LOCALE_EN_US_SIZE = strlen(LOCALE_EN_US);
-        return localeStr && strlen(localeStr) >= LOCALE_EN_US_SIZE
-                && strncmp(localeStr, LOCALE_EN_US, LOCALE_EN_US_SIZE) == 0;
+    AK_FORCE_INLINE static bool isEnLocale(const std::vector<int> *locale) {
+        const int NCHARS = NELEMS(LOCALE_EN_US);
+        if (locale->size() < NCHARS) {
+            return false;
+        }
+        for (int i = 0; i < NCHARS; ++i) {
+            if ((*locale)[i] != LOCALE_EN_US[i]) {
+                return false;
+            }
+        }
+        return true;
     }
 
  public:
-    static int getAdditionalCharsSize(const char *const localeStr, const int c) {
-        if (!isEnLocale(localeStr)) {
+    static int getAdditionalCharsSize(const std::vector<int> *locale, const int c) {
+        if (!isEnLocale(locale)) {
             return 0;
         }
         switch (c) {
@@ -65,8 +74,8 @@ class AdditionalProximityChars {
         }
     }
 
-    static const int *getAdditionalChars(const char *const localeStr, const int c) {
-        if (!isEnLocale(localeStr)) {
+    static const int *getAdditionalChars(const std::vector<int> *locale, const int c) {
+        if (!isEnLocale(locale)) {
             return 0;
         }
         switch (c) {
diff --git a/native/jni/src/suggest/core/layout/geometry_utils.h b/native/jni/src/suggest/core/layout/geometry_utils.h
index b667df68f..000fcd4a1 100644
--- a/native/jni/src/suggest/core/layout/geometry_utils.h
+++ b/native/jni/src/suggest/core/layout/geometry_utils.h
@@ -38,13 +38,15 @@ class GeometryUtils {
     }
 
     static AK_FORCE_INLINE float getAngleDiff(const float a1, const float a2) {
-        const float deltaA = fabsf(a1 - a2);
-        const float diff = ROUND_FLOAT_10000(deltaA);
-        if (diff > M_PI_F) {
-            const float normalizedDiff = 2.0f * M_PI_F - diff;
-            return ROUND_FLOAT_10000(normalizedDiff);
+        static const float M_2PI_F = M_PI * 2.0f;
+        float delta = fabsf(a1 - a2);
+        if (delta > M_2PI_F) {
+            delta -= (M_2PI_F * static_cast<int>(delta / M_2PI_F));
         }
-        return diff;
+        if (delta > M_PI_F) {
+            delta = M_2PI_F - delta;
+        }
+        return ROUND_FLOAT_10000(delta);
     }
 
     static AK_FORCE_INLINE int getDistanceInt(const int x1, const int y1, const int x2,
diff --git a/native/jni/src/suggest/core/layout/proximity_info.cpp b/native/jni/src/suggest/core/layout/proximity_info.cpp
index 4c75a188e..933a5e145 100644
--- a/native/jni/src/suggest/core/layout/proximity_info.cpp
+++ b/native/jni/src/suggest/core/layout/proximity_info.cpp
@@ -49,13 +49,13 @@ static AK_FORCE_INLINE void safeGetOrFillZeroFloatArrayRegion(JNIEnv *env, jfloa
     }
 }
 
-ProximityInfo::ProximityInfo(JNIEnv *env, const jstring localeJStr,
-        const int keyboardWidth, const int keyboardHeight, const int gridWidth,
-        const int gridHeight, const int mostCommonKeyWidth, const int mostCommonKeyHeight,
-        const jintArray proximityChars, const int keyCount, const jintArray keyXCoordinates,
-        const jintArray keyYCoordinates, const jintArray keyWidths, const jintArray keyHeights,
-        const jintArray keyCharCodes, const jfloatArray sweetSpotCenterXs,
-        const jfloatArray sweetSpotCenterYs, const jfloatArray sweetSpotRadii)
+ProximityInfo::ProximityInfo(JNIEnv *env, const int keyboardWidth, const int keyboardHeight,
+        const int gridWidth, const int gridHeight, const int mostCommonKeyWidth,
+        const int mostCommonKeyHeight, const jintArray proximityChars, const int keyCount,
+        const jintArray keyXCoordinates, const jintArray keyYCoordinates,
+        const jintArray keyWidths, const jintArray keyHeights, const jintArray keyCharCodes,
+        const jfloatArray sweetSpotCenterXs, const jfloatArray sweetSpotCenterYs,
+        const jfloatArray sweetSpotRadii)
         : GRID_WIDTH(gridWidth), GRID_HEIGHT(gridHeight), MOST_COMMON_KEY_WIDTH(mostCommonKeyWidth),
           MOST_COMMON_KEY_WIDTH_SQUARE(mostCommonKeyWidth * mostCommonKeyWidth),
           NORMALIZED_SQUARED_MOST_COMMON_KEY_HYPOTENUSE(1.0f +
@@ -82,13 +82,6 @@ ProximityInfo::ProximityInfo(JNIEnv *env, const jstring localeJStr,
     if (DEBUG_PROXIMITY_INFO) {
         AKLOGI("Create proximity info array %d", proximityCharsLength);
     }
-    const jsize localeCStrUtf8Length = env->GetStringUTFLength(localeJStr);
-    if (localeCStrUtf8Length >= MAX_LOCALE_STRING_LENGTH) {
-        AKLOGI("Locale string length too long: length=%d", localeCStrUtf8Length);
-        ASSERT(false);
-    }
-    memset(mLocaleStr, 0, sizeof(mLocaleStr));
-    env->GetStringUTFRegion(localeJStr, 0, env->GetStringLength(localeJStr), mLocaleStr);
     safeGetOrFillZeroIntArrayRegion(env, proximityChars, proximityCharsLength,
             mProximityCharsArray);
     safeGetOrFillZeroIntArrayRegion(env, keyXCoordinates, KEY_COUNT, mKeyXCoordinates);
diff --git a/native/jni/src/suggest/core/layout/proximity_info.h b/native/jni/src/suggest/core/layout/proximity_info.h
index d4e453736..f7c907697 100644
--- a/native/jni/src/suggest/core/layout/proximity_info.h
+++ b/native/jni/src/suggest/core/layout/proximity_info.h
@@ -18,6 +18,7 @@
 #define LATINIME_PROXIMITY_INFO_H
 
 #include <unordered_map>
+#include <vector>
 
 #include "defines.h"
 #include "jni.h"
@@ -27,9 +28,9 @@ namespace latinime {
 
 class ProximityInfo {
  public:
-    ProximityInfo(JNIEnv *env, const jstring localeJStr,
-            const int keyboardWidth, const int keyboardHeight, const int gridWidth,
-            const int gridHeight, const int mostCommonKeyWidth, const int mostCommonKeyHeight,
+    ProximityInfo(JNIEnv *env, const int keyboardWidth, const int keyboardHeight,
+            const int gridWidth, const int gridHeight,
+            const int mostCommonKeyWidth, const int mostCommonKeyHeight,
             const jintArray proximityChars, const int keyCount, const jintArray keyXCoordinates,
             const jintArray keyYCoordinates, const jintArray keyWidths, const jintArray keyHeights,
             const jintArray keyCharCodes, const jfloatArray sweetSpotCenterXs,
@@ -71,11 +72,11 @@ class ProximityInfo {
 
     AK_FORCE_INLINE void initializeProximities(const int *const inputCodes,
             const int *const inputXCoordinates, const int *const inputYCoordinates,
-            const int inputSize, int *allInputCodes) const {
+            const int inputSize, int *allInputCodes, const std::vector<int> *locale) const {
         ProximityInfoUtils::initializeProximities(inputCodes, inputXCoordinates, inputYCoordinates,
                 inputSize, mKeyXCoordinates, mKeyYCoordinates, mKeyWidths, mKeyHeights,
                 mProximityCharsArray, CELL_HEIGHT, CELL_WIDTH, GRID_WIDTH, MOST_COMMON_KEY_WIDTH,
-                KEY_COUNT, mLocaleStr, &mLowerCodePointToKeyMap, allInputCodes);
+                KEY_COUNT, locale, &mLowerCodePointToKeyMap, allInputCodes);
     }
 
     AK_FORCE_INLINE int getKeyIndexOf(const int c) const {
@@ -103,9 +104,6 @@ class ProximityInfo {
     const int KEYBOARD_HEIGHT;
     const float KEYBOARD_HYPOTENUSE;
     const bool HAS_TOUCH_POSITION_CORRECTION_DATA;
-    // Assuming locale strings such as en_US, sr-Latn etc.
-    static const int MAX_LOCALE_STRING_LENGTH = 10;
-    char mLocaleStr[MAX_LOCALE_STRING_LENGTH];
     int *mProximityCharsArray;
     int mKeyXCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
     int mKeyYCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
diff --git a/native/jni/src/suggest/core/layout/proximity_info_state.cpp b/native/jni/src/suggest/core/layout/proximity_info_state.cpp
index 91469e26d..d43a0026a 100644
--- a/native/jni/src/suggest/core/layout/proximity_info_state.cpp
+++ b/native/jni/src/suggest/core/layout/proximity_info_state.cpp
@@ -42,7 +42,7 @@ int ProximityInfoState::getPrimaryOriginalCodePointAt(const int index) const {
 void ProximityInfoState::initInputParams(const int pointerId, const float maxPointToKeyLength,
         const ProximityInfo *proximityInfo, const int *const inputCodes, const int inputSize,
         const int *const xCoordinates, const int *const yCoordinates, const int *const times,
-        const int *const pointerIds, const bool isGeometric) {
+        const int *const pointerIds, const bool isGeometric, const std::vector<int> *locale) {
     ASSERT(isGeometric || (inputSize < MAX_WORD_LENGTH));
     mIsContinuousSuggestionPossible = (mHasBeenUpdatedByGeometricInput != isGeometric) ?
             false : ProximityInfoStateUtils::checkAndReturnIsContinuousSuggestionPossible(
@@ -66,7 +66,7 @@ void ProximityInfoState::initInputParams(const int pointerId, const float maxPoi
 
     if (!isGeometric && pointerId == 0) {
         mProximityInfo->initializeProximities(inputCodes, xCoordinates, yCoordinates,
-                inputSize, mInputProximities);
+                inputSize, mInputProximities, locale);
     }
 
     ///////////////////////
diff --git a/native/jni/src/suggest/core/layout/proximity_info_state.h b/native/jni/src/suggest/core/layout/proximity_info_state.h
index e6180fe17..a2d663544 100644
--- a/native/jni/src/suggest/core/layout/proximity_info_state.h
+++ b/native/jni/src/suggest/core/layout/proximity_info_state.h
@@ -37,7 +37,8 @@ class ProximityInfoState {
     void initInputParams(const int pointerId, const float maxPointToKeyLength,
             const ProximityInfo *proximityInfo, const int *const inputCodes,
             const int inputSize, const int *xCoordinates, const int *yCoordinates,
-            const int *const times, const int *const pointerIds, const bool isGeometric);
+            const int *const times, const int *const pointerIds, const bool isGeometric,
+            const std::vector<int> *locale);
 
     /////////////////////////////////////////
     // Defined here                        //
diff --git a/native/jni/src/suggest/core/layout/proximity_info_utils.h b/native/jni/src/suggest/core/layout/proximity_info_utils.h
index 178aada2d..79d0615b8 100644
--- a/native/jni/src/suggest/core/layout/proximity_info_utils.h
+++ b/native/jni/src/suggest/core/layout/proximity_info_utils.h
@@ -19,6 +19,7 @@
 
 #include <cmath>
 #include <unordered_map>
+#include <vector>
 
 #include "defines.h"
 #include "suggest/core/layout/additional_proximity_chars.h"
@@ -51,7 +52,7 @@ class ProximityInfoUtils {
             const int *const keyYCoordinates, const int *const keyWidths, const int *keyHeights,
             const int *const proximityCharsArray, const int cellHeight, const int cellWidth,
             const int gridWidth, const int mostCommonKeyWidth, const int keyCount,
-            const char *const localeStr,
+            const std::vector<int> *locale,
             const std::unordered_map<int, int> *const codeToKeyMap, int *inputProximities) {
         // Initialize
         // - mInputCodes
@@ -64,7 +65,7 @@ class ProximityInfoUtils {
             int *proximities = &inputProximities[i * MAX_PROXIMITY_CHARS_SIZE];
             calculateProximities(keyXCoordinates, keyYCoordinates, keyWidths, keyHeights,
                     proximityCharsArray, cellHeight, cellWidth, gridWidth, mostCommonKeyWidth,
-                    keyCount, x, y, primaryKey, localeStr, codeToKeyMap, proximities);
+                    keyCount, x, y, primaryKey, locale, codeToKeyMap, proximities);
         }
 
         if (DEBUG_PROXIMITY_CHARS) {
@@ -143,7 +144,7 @@ class ProximityInfoUtils {
             const int *const keyYCoordinates, const int *const keyWidths, const int *keyHeights,
             const int *const proximityCharsArray, const int cellHeight, const int cellWidth,
             const int gridWidth, const int mostCommonKeyWidth, const int keyCount,
-            const int x, const int y, const int primaryKey, const char *const localeStr,
+            const int x, const int y, const int primaryKey, const std::vector<int> *locale,
             const std::unordered_map<int, int> *const codeToKeyMap, int *proximities) {
         const int mostCommonKeyWidthSquare = mostCommonKeyWidth * mostCommonKeyWidth;
         int insertPos = 0;
@@ -177,7 +178,7 @@ class ProximityInfoUtils {
                 }
             }
             const int additionalProximitySize =
-                    AdditionalProximityChars::getAdditionalCharsSize(localeStr, primaryKey);
+                    AdditionalProximityChars::getAdditionalCharsSize(locale, primaryKey);
             if (additionalProximitySize > 0) {
                 proximities[insertPos++] = ADDITIONAL_PROXIMITY_CHAR_DELIMITER_CODE;
                 if (insertPos >= MAX_PROXIMITY_CHARS_SIZE) {
@@ -188,7 +189,7 @@ class ProximityInfoUtils {
                 }
 
                 const int *additionalProximityChars =
-                        AdditionalProximityChars::getAdditionalChars(localeStr, primaryKey);
+                        AdditionalProximityChars::getAdditionalChars(locale, primaryKey);
                 for (int j = 0; j < additionalProximitySize; ++j) {
                     const int ac = additionalProximityChars[j];
                     int k = 0;
diff --git a/native/jni/src/suggest/core/policy/scoring.h b/native/jni/src/suggest/core/policy/scoring.h
index 9e75cace4..b9dda83ad 100644
--- a/native/jni/src/suggest/core/policy/scoring.h
+++ b/native/jni/src/suggest/core/policy/scoring.h
@@ -30,11 +30,13 @@ class Scoring {
  public:
     virtual int calculateFinalScore(const float compoundDistance, const int inputSize,
             const ErrorTypeUtils::ErrorType containedErrorTypes, const bool forceCommit,
-            const bool boostExactMatches) const = 0;
+            const bool boostExactMatches, const bool hasProbabilityZero) const = 0;
     virtual void getMostProbableString(const DicTraverseSession *const traverseSession,
-            const float languageWeight, SuggestionResults *const outSuggestionResults) const = 0;
-    virtual float getAdjustedLanguageWeight(DicTraverseSession *const traverseSession,
-            DicNode *const terminals, const int size) const = 0;
+            const float weightOfLangModelVsSpatialModel,
+            SuggestionResults *const outSuggestionResults) const = 0;
+    virtual float getAdjustedWeightOfLangModelVsSpatialModel(
+            DicTraverseSession *const traverseSession, DicNode *const terminals,
+            const int size) const = 0;
     virtual float getDoubleLetterDemotionDistanceCost(
             const DicNode *const terminalDicNode) const = 0;
     virtual bool autoCorrectsToMultiWordSuggestionIfTop() const = 0;
diff --git a/native/jni/src/suggest/core/policy/traversal.h b/native/jni/src/suggest/core/policy/traversal.h
index 8ddaa0514..5b6616d9a 100644
--- a/native/jni/src/suggest/core/policy/traversal.h
+++ b/native/jni/src/suggest/core/policy/traversal.h
@@ -44,11 +44,12 @@ class Traversal {
     virtual bool needsToTraverseAllUserInput() const = 0;
     virtual float getMaxSpatialDistance() const = 0;
     virtual int getDefaultExpandDicNodeSize() const = 0;
-    virtual int getMaxCacheSize(const int inputSize) const = 0;
+    virtual int getMaxCacheSize(const int inputSize, const float weightForLocale) const = 0;
     virtual int getTerminalCacheSize() const = 0;
     virtual bool isPossibleOmissionChildNode(const DicTraverseSession *const traverseSession,
             const DicNode *const parentDicNode, const DicNode *const dicNode) const = 0;
-    virtual bool isGoodToTraverseNextWord(const DicNode *const dicNode) const = 0;
+    virtual bool isGoodToTraverseNextWord(const DicNode *const dicNode,
+            const int probability) const = 0;
 
  protected:
     Traversal() {}
diff --git a/native/jni/src/suggest/core/policy/weighting.cpp b/native/jni/src/suggest/core/policy/weighting.cpp
index c202b81fe..450203d98 100644
--- a/native/jni/src/suggest/core/policy/weighting.cpp
+++ b/native/jni/src/suggest/core/policy/weighting.cpp
@@ -110,12 +110,16 @@ static inline void profile(const CorrectionType correctionType, DicNode *const n
         return weighting->getOmissionCost(parentDicNode, dicNode);
     case CT_ADDITIONAL_PROXIMITY:
         // only used for typing
-        return weighting->getAdditionalProximityCost();
+        // TODO: Quit calling getMatchedCost().
+        return weighting->getAdditionalProximityCost()
+                + weighting->getMatchedCost(traverseSession, dicNode, inputStateG);
     case CT_SUBSTITUTION:
         // only used for typing
-        return weighting->getSubstitutionCost();
+        // TODO: Quit calling getMatchedCost().
+        return weighting->getSubstitutionCost()
+                + weighting->getMatchedCost(traverseSession, dicNode, inputStateG);
     case CT_NEW_WORD_SPACE_OMISSION:
-        return weighting->getNewWordSpatialCost(traverseSession, dicNode, inputStateG);
+        return weighting->getSpaceOmissionCost(traverseSession, dicNode, inputStateG);
     case CT_MATCH:
         return weighting->getMatchedCost(traverseSession, dicNode, inputStateG);
     case CT_COMPLETION:
@@ -176,9 +180,9 @@ static inline void profile(const CorrectionType correctionType, DicNode *const n
         case CT_OMISSION:
             return 0;
         case CT_ADDITIONAL_PROXIMITY:
-            return 0; /* 0 because CT_MATCH will be called */
+            return 1;
         case CT_SUBSTITUTION:
-            return 0; /* 0 because CT_MATCH will be called */
+            return 1;
         case CT_NEW_WORD_SPACE_OMISSION:
             return 0;
         case CT_MATCH:
diff --git a/native/jni/src/suggest/core/policy/weighting.h b/native/jni/src/suggest/core/policy/weighting.h
index bd6b3cf41..863c4eabe 100644
--- a/native/jni/src/suggest/core/policy/weighting.h
+++ b/native/jni/src/suggest/core/policy/weighting.h
@@ -57,7 +57,7 @@ class Weighting {
             const DicTraverseSession *const traverseSession,
             const DicNode *const parentDicNode, const DicNode *const dicNode) const = 0;
 
-    virtual float getNewWordSpatialCost(const DicTraverseSession *const traverseSession,
+    virtual float getSpaceOmissionCost(const DicTraverseSession *const traverseSession,
             const DicNode *const dicNode, DicNode_InputStateG *const inputStateG) const = 0;
 
     virtual float getNewWordBigramLanguageCost(
diff --git a/native/jni/src/suggest/core/result/suggestion_results.cpp b/native/jni/src/suggest/core/result/suggestion_results.cpp
index 4c10bd08a..3756d1092 100644
--- a/native/jni/src/suggest/core/result/suggestion_results.cpp
+++ b/native/jni/src/suggest/core/result/suggestion_results.cpp
@@ -23,7 +23,7 @@ namespace latinime {
 void SuggestionResults::outputSuggestions(JNIEnv *env, jintArray outSuggestionCount,
         jintArray outputCodePointsArray, jintArray outScoresArray, jintArray outSpaceIndicesArray,
         jintArray outTypesArray, jintArray outAutoCommitFirstWordConfidenceArray,
-        jfloatArray outLanguageWeight) {
+        jfloatArray outWeightOfLangModelVsSpatialModel) {
     int outputIndex = 0;
     while (!mSuggestedWords.empty()) {
         const SuggestedWord &suggestedWord = mSuggestedWords.top();
@@ -44,7 +44,8 @@ void SuggestionResults::outputSuggestions(JNIEnv *env, jintArray outSuggestionCo
         mSuggestedWords.pop();
     }
     JniDataUtils::putIntToArray(env, outSuggestionCount, 0 /* index */, outputIndex);
-    JniDataUtils::putFloatToArray(env, outLanguageWeight, 0 /* index */, mLanguageWeight);
+    JniDataUtils::putFloatToArray(env, outWeightOfLangModelVsSpatialModel, 0 /* index */,
+            mWeightOfLangModelVsSpatialModel);
 }
 
 void SuggestionResults::addPrediction(const int *const codePoints, const int codePointCount,
@@ -89,7 +90,7 @@ void SuggestionResults::getSortedScores(int *const outScores) const {
 }
 
 void SuggestionResults::dumpSuggestions() const {
-    AKLOGE("language weight: %f", mLanguageWeight);
+    AKLOGE("weight of language model vs spatial model: %f", mWeightOfLangModelVsSpatialModel);
     std::vector<SuggestedWord> suggestedWords;
     auto copyOfSuggestedWords = mSuggestedWords;
     while (!copyOfSuggestedWords.empty()) {
diff --git a/native/jni/src/suggest/core/result/suggestion_results.h b/native/jni/src/suggest/core/result/suggestion_results.h
index 8e845e2d3..738c78a9f 100644
--- a/native/jni/src/suggest/core/result/suggestion_results.h
+++ b/native/jni/src/suggest/core/result/suggestion_results.h
@@ -29,13 +29,15 @@ namespace latinime {
 class SuggestionResults {
  public:
     explicit SuggestionResults(const int maxSuggestionCount)
-            : mMaxSuggestionCount(maxSuggestionCount), mLanguageWeight(NOT_A_LANGUAGE_WEIGHT),
+            : mMaxSuggestionCount(maxSuggestionCount),
+              mWeightOfLangModelVsSpatialModel(NOT_A_WEIGHT_OF_LANG_MODEL_VS_SPATIAL_MODEL),
               mSuggestedWords() {}
 
     // Returns suggestion count.
     void outputSuggestions(JNIEnv *env, jintArray outSuggestionCount, jintArray outCodePointsArray,
             jintArray outScoresArray, jintArray outSpaceIndicesArray, jintArray outTypesArray,
-            jintArray outAutoCommitFirstWordConfidenceArray, jfloatArray outLanguageWeight);
+            jintArray outAutoCommitFirstWordConfidenceArray,
+            jfloatArray outWeightOfLangModelVsSpatialModel);
     void addPrediction(const int *const codePoints, const int codePointCount, const int score);
     void addSuggestion(const int *const codePoints, const int codePointCount,
             const int score, const int type, const int indexToPartialCommit,
@@ -43,8 +45,8 @@ class SuggestionResults {
     void getSortedScores(int *const outScores) const;
     void dumpSuggestions() const;
 
-    void setLanguageWeight(const float languageWeight) {
-        mLanguageWeight = languageWeight;
+    void setWeightOfLangModelVsSpatialModel(const float weightOfLangModelVsSpatialModel) {
+        mWeightOfLangModelVsSpatialModel = weightOfLangModelVsSpatialModel;
     }
 
     int getSuggestionCount() const {
@@ -55,7 +57,7 @@ class SuggestionResults {
     DISALLOW_IMPLICIT_CONSTRUCTORS(SuggestionResults);
 
     const int mMaxSuggestionCount;
-    float mLanguageWeight;
+    float mWeightOfLangModelVsSpatialModel;
     std::priority_queue<
             SuggestedWord, std::vector<SuggestedWord>, SuggestedWord::Comparator> mSuggestedWords;
 };
diff --git a/native/jni/src/suggest/core/result/suggestions_output_utils.cpp b/native/jni/src/suggest/core/result/suggestions_output_utils.cpp
index 0b99b75ec..7c37241de 100644
--- a/native/jni/src/suggest/core/result/suggestions_output_utils.cpp
+++ b/native/jni/src/suggest/core/result/suggestions_output_utils.cpp
@@ -19,9 +19,9 @@
 #include <algorithm>
 #include <vector>
 
+#include "dictionary/utils/binary_dictionary_shortcut_iterator.h"
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_utils.h"
-#include "suggest/core/dictionary/binary_dictionary_shortcut_iterator.h"
 #include "suggest/core/dictionary/error_type_utils.h"
 #include "suggest/core/policy/scoring.h"
 #include "suggest/core/result/suggestion_results.h"
@@ -34,7 +34,8 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
 
 /* static */ void SuggestionsOutputUtils::outputSuggestions(
         const Scoring *const scoringPolicy, DicTraverseSession *traverseSession,
-        const float languageWeight, SuggestionResults *const outSuggestionResults) {
+        const float weightOfLangModelVsSpatialModel,
+        SuggestionResults *const outSuggestionResults) {
 #if DEBUG_EVALUATE_MOST_PROBABLE_STRING
     const int terminalSize = 0;
 #else
@@ -44,12 +45,15 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
     for (int index = terminalSize - 1; index >= 0; --index) {
         traverseSession->getDicTraverseCache()->popTerminal(&terminals[index]);
     }
-    // Compute a language weight when an invalid language weight is passed.
-    // NOT_A_LANGUAGE_WEIGHT (-1) is assumed as an invalid language weight.
-    const float languageWeightToOutputSuggestions = (languageWeight < 0.0f) ?
-            scoringPolicy->getAdjustedLanguageWeight(
-                    traverseSession, terminals.data(), terminalSize) : languageWeight;
-    outSuggestionResults->setLanguageWeight(languageWeightToOutputSuggestions);
+    // Compute a weight of language model when an invalid weight is passed.
+    // NOT_A_WEIGHT_OF_LANG_MODEL_VS_SPATIAL_MODEL (-1) is taken as an invalid value.
+    const float weightOfLangModelVsSpatialModelToOutputSuggestions =
+            (weightOfLangModelVsSpatialModel < 0.0f)
+            ? scoringPolicy->getAdjustedWeightOfLangModelVsSpatialModel(traverseSession,
+                    terminals.data(), terminalSize)
+            : weightOfLangModelVsSpatialModel;
+    outSuggestionResults->setWeightOfLangModelVsSpatialModel(
+            weightOfLangModelVsSpatialModelToOutputSuggestions);
     // Force autocorrection for obvious long multi-word suggestions when the top suggestion is
     // a long multiple words suggestion.
     // TODO: Implement a smarter auto-commit method for handling multi-word suggestions.
@@ -65,16 +69,62 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
     // Output suggestion results here
     for (auto &terminalDicNode : terminals) {
         outputSuggestionsOfDicNode(scoringPolicy, traverseSession, &terminalDicNode,
-                languageWeightToOutputSuggestions, boostExactMatches, forceCommitMultiWords,
-                outputSecondWordFirstLetterInputIndex, outSuggestionResults);
+                weightOfLangModelVsSpatialModelToOutputSuggestions, boostExactMatches,
+                forceCommitMultiWords, outputSecondWordFirstLetterInputIndex, outSuggestionResults);
+    }
+    scoringPolicy->getMostProbableString(traverseSession,
+            weightOfLangModelVsSpatialModelToOutputSuggestions, outSuggestionResults);
+}
+
+/* static */ bool SuggestionsOutputUtils::shouldBlockWord(
+        const SuggestOptions *const suggestOptions, const DicNode *const terminalDicNode,
+        const WordAttributes wordAttributes, const bool isLastWord) {
+    const bool currentWordExactMatch =
+            ErrorTypeUtils::isExactMatch(terminalDicNode->getContainedErrorTypes());
+    // When we have to block offensive words, non-exact matched offensive words should not be
+    // output.
+    const bool shouldBlockOffensiveWords = suggestOptions->blockOffensiveWords();
+
+    const bool isBlockedOffensiveWord = shouldBlockOffensiveWords &&
+            wordAttributes.isPossiblyOffensive();
+
+    // This function is called in two situations:
+    //
+    // 1) At the end of a search, in which case terminalDicNode will point to the last DicNode
+    //    of the search, and isLastWord will be true.
+    //                    "fuck"
+    //                        |
+    //                        \ terminalDicNode (isLastWord=true, currentWordExactMatch=true)
+    //    In this case, if the current word is an exact match, we will always let the word
+    //    through, even if the user is blocking offensive words (it's exactly what they typed!)
+    //
+    // 2) In the middle of the search, when we hit a terminal node, to decide whether or not
+    //    to start a new search at root, to try to match the rest of the input. In this case,
+    //    terminalDicNode will point to the terminal node we just hit, and isLastWord will be
+    //    false.
+    //                    "fuckvthis"
+    //                        |
+    //                        \ terminalDicNode (isLastWord=false, currentWordExactMatch=true)
+    //
+    // In this case, we should NOT allow the match through (correcting "fuckthis" to "fuck this"
+    // when offensive words are blocked would be a bad idea).
+    //
+    // In the case of a multi-word correction where the offensive word is typed last (eg.
+    // for the input "allfuck"), this function will be called with isLastWord==true, but
+    // currentWordExactMatch==false. So we are OK in this case as well.
+    //                    "allfuck"
+    //                           |
+    //                           \ terminalDicNode (isLastWord=true, currentWordExactMatch=false)
+    if (isLastWord && currentWordExactMatch) {
+        return false;
+    } else {
+        return isBlockedOffensiveWord;
     }
-    scoringPolicy->getMostProbableString(traverseSession, languageWeightToOutputSuggestions,
-            outSuggestionResults);
 }
 
 /* static */ void SuggestionsOutputUtils::outputSuggestionsOfDicNode(
         const Scoring *const scoringPolicy, DicTraverseSession *traverseSession,
-        const DicNode *const terminalDicNode, const float languageWeight,
+        const DicNode *const terminalDicNode, const float weightOfLangModelVsSpatialModel,
         const bool boostExactMatches, const bool forceCommitMultiWords,
         const bool outputSecondWordFirstLetterInputIndex,
         SuggestionResults *const outSuggestionResults) {
@@ -83,34 +133,32 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
     }
     const float doubleLetterCost =
             scoringPolicy->getDoubleLetterDemotionDistanceCost(terminalDicNode);
-    const float compoundDistance = terminalDicNode->getCompoundDistance(languageWeight)
-            + doubleLetterCost;
-    const bool isPossiblyOffensiveWord =
-            traverseSession->getDictionaryStructurePolicy()->getProbability(
-                    terminalDicNode->getProbability(), NOT_A_PROBABILITY) <= 0;
+    const float compoundDistance =
+            terminalDicNode->getCompoundDistance(weightOfLangModelVsSpatialModel)
+                    + doubleLetterCost;
+    const WordAttributes wordAttributes = traverseSession->getDictionaryStructurePolicy()
+            ->getWordAttributesInContext(terminalDicNode->getPrevWordIds(),
+                    terminalDicNode->getWordId(), nullptr /* multiBigramMap */);
     const bool isExactMatch =
             ErrorTypeUtils::isExactMatch(terminalDicNode->getContainedErrorTypes());
     const bool isExactMatchWithIntentionalOmission =
             ErrorTypeUtils::isExactMatchWithIntentionalOmission(
                     terminalDicNode->getContainedErrorTypes());
-    const bool isFirstCharUppercase = terminalDicNode->isFirstCharUppercase();
-    // Heuristic: We exclude probability=0 first-char-uppercase words from exact match.
-    // (e.g. "AMD" and "and")
-    const bool isSafeExactMatch = isExactMatch
-            && !(isPossiblyOffensiveWord && isFirstCharUppercase);
+    // TODO: Decide whether the word should be auto-corrected or not here.
+    const bool isAppropriateForAutoCorrection = !ErrorTypeUtils::isMissingExplicitAccent(
+            terminalDicNode->getContainedErrorTypes());
     const int outputTypeFlags =
-            (isPossiblyOffensiveWord ? Dictionary::KIND_FLAG_POSSIBLY_OFFENSIVE : 0)
-            | ((isSafeExactMatch && boostExactMatches) ? Dictionary::KIND_FLAG_EXACT_MATCH : 0)
+            (wordAttributes.isPossiblyOffensive() ? Dictionary::KIND_FLAG_POSSIBLY_OFFENSIVE : 0)
+            | ((isExactMatch && boostExactMatches) ? Dictionary::KIND_FLAG_EXACT_MATCH : 0)
             | (isExactMatchWithIntentionalOmission ?
-                    Dictionary::KIND_FLAG_EXACT_MATCH_WITH_INTENTIONAL_OMISSION : 0);
-
+                    Dictionary::KIND_FLAG_EXACT_MATCH_WITH_INTENTIONAL_OMISSION : 0)
+            | (isAppropriateForAutoCorrection ?
+                    Dictionary::KIND_FLAG_APPROPRIATE_FOR_AUTOCORRECTION : 0);
     // Entries that are blacklisted or do not represent a word should not be output.
-    const bool isValidWord = !terminalDicNode->isBlacklistedOrNotAWord();
-    // When we have to block offensive words, non-exact matched offensive words should not be
-    // output.
-    const bool blockOffensiveWords = traverseSession->getSuggestOptions()->blockOffensiveWords();
-    const bool isBlockedOffensiveWord = blockOffensiveWords && isPossiblyOffensiveWord
-            && !isSafeExactMatch;
+    const bool isValidWord = !(wordAttributes.isBlacklisted() || wordAttributes.isNotAWord());
+
+    const bool shouldBlockThisWord = shouldBlockWord(traverseSession->getSuggestOptions(),
+            terminalDicNode, wordAttributes, true /* isLastWord */);
 
     // Increase output score of top typing suggestion to ensure autocorrection.
     // TODO: Better integration with java side autocorrection logic.
@@ -118,11 +166,11 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
             compoundDistance, traverseSession->getInputSize(),
             terminalDicNode->getContainedErrorTypes(),
             (forceCommitMultiWords && terminalDicNode->hasMultipleWords()),
-            boostExactMatches);
+            boostExactMatches, wordAttributes.getProbability() == 0);
 
     // Don't output invalid or blocked offensive words. However, we still need to submit their
     // shortcuts if any.
-    if (isValidWord && !isBlockedOffensiveWord) {
+    if (isValidWord && !shouldBlockThisWord) {
         int codePoints[MAX_WORD_LENGTH];
         terminalDicNode->outputResult(codePoints);
         const int indexToPartialCommit = outputSecondWordFirstLetterInputIndex ?
@@ -139,10 +187,9 @@ const int SuggestionsOutputUtils::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
     // Shortcut is not supported for multiple words suggestions.
     // TODO: Check shortcuts during traversal for multiple words suggestions.
     if (!terminalDicNode->hasMultipleWords()) {
-        BinaryDictionaryShortcutIterator shortcutIt(
-                traverseSession->getDictionaryStructurePolicy()->getShortcutsStructurePolicy(),
-                traverseSession->getDictionaryStructurePolicy()
-                        ->getShortcutPositionOfPtNode(terminalDicNode->getPtNodePos()));
+        BinaryDictionaryShortcutIterator shortcutIt =
+                traverseSession->getDictionaryStructurePolicy()->getShortcutIterator(
+                        terminalDicNode->getWordId());
         const bool sameAsTyped = scoringPolicy->sameAsTyped(traverseSession, terminalDicNode);
         outputShortcuts(&shortcutIt, finalScore, sameAsTyped, outSuggestionResults);
     }
diff --git a/native/jni/src/suggest/core/result/suggestions_output_utils.h b/native/jni/src/suggest/core/result/suggestions_output_utils.h
index b099b4776..bcb75a483 100644
--- a/native/jni/src/suggest/core/result/suggestions_output_utils.h
+++ b/native/jni/src/suggest/core/result/suggestions_output_utils.h
@@ -18,6 +18,7 @@
 #define LATINIME_SUGGESTIONS_OUTPUT_UTILS
 
 #include "defines.h"
+#include "dictionary/property/word_attributes.h"
 
 namespace latinime {
 
@@ -25,15 +26,23 @@ class BinaryDictionaryShortcutIterator;
 class DicNode;
 class DicTraverseSession;
 class Scoring;
+class SuggestOptions;
 class SuggestionResults;
 
 class SuggestionsOutputUtils {
  public:
     /**
+     * Returns true if we should block the incoming word, in the context of the user's
+     * preferences to include or not include possibly offensive words
+     */
+    static bool shouldBlockWord(const SuggestOptions *const suggestOptions,
+            const DicNode *const terminalDicNode, const WordAttributes wordAttributes,
+            const bool isLastWord);
+    /**
      * Outputs the final list of suggestions (i.e., terminal nodes).
      */
     static void outputSuggestions(const Scoring *const scoringPolicy,
-            DicTraverseSession *traverseSession, const float languageWeight,
+            DicTraverseSession *traverseSession, const float weightOfLangModelVsSpatialModel,
             SuggestionResults *const outSuggestionResults);
 
  private:
@@ -44,7 +53,7 @@ class SuggestionsOutputUtils {
 
     static void outputSuggestionsOfDicNode(const Scoring *const scoringPolicy,
             DicTraverseSession *traverseSession, const DicNode *const terminalDicNode,
-            const float languageWeight, const bool boostExactMatches,
+            const float weightOfLangModelVsSpatialModel, const bool boostExactMatches,
             const bool forceCommitMultiWords, const bool outputSecondWordFirstLetterInputIndex,
             SuggestionResults *const outSuggestionResults);
     static void outputShortcuts(BinaryDictionaryShortcutIterator *const shortcutIt,
diff --git a/native/jni/src/suggest/core/session/dic_traverse_session.cpp b/native/jni/src/suggest/core/session/dic_traverse_session.cpp
index f1e411f38..d7dd5a02d 100644
--- a/native/jni/src/suggest/core/session/dic_traverse_session.cpp
+++ b/native/jni/src/suggest/core/session/dic_traverse_session.cpp
@@ -17,10 +17,10 @@
 #include "suggest/core/session/dic_traverse_session.h"
 
 #include "defines.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/property/ngram_context.h"
 #include "suggest/core/dictionary/dictionary.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "suggest/core/session/prev_words_info.h"
 
 namespace latinime {
 
@@ -30,13 +30,13 @@ const int DicTraverseSession::DICTIONARY_SIZE_THRESHOLD_TO_USE_LARGE_CACHE_FOR_S
         256 * 1024;
 
 void DicTraverseSession::init(const Dictionary *const dictionary,
-        const PrevWordsInfo *const prevWordsInfo, const SuggestOptions *const suggestOptions) {
+        const NgramContext *const ngramContext, const SuggestOptions *const suggestOptions) {
     mDictionary = dictionary;
     mMultiWordCostMultiplier = getDictionaryStructurePolicy()->getHeaderStructurePolicy()
             ->getMultiWordCostMultiplier();
     mSuggestOptions = suggestOptions;
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(
-            getDictionaryStructurePolicy(), mPrevWordsPtNodePos, true /* tryLowerCaseSearch */);
+    mPrevWordIdCount = ngramContext->getPrevWordIds(getDictionaryStructurePolicy(),
+            &mPrevWordIdArray, true /* tryLowerCaseSearch */).size();
 }
 
 void DicTraverseSession::setupForGetSuggestions(const ProximityInfo *pInfo,
@@ -69,8 +69,12 @@ void DicTraverseSession::initializeProximityInfoStates(const int *const inputCod
     for (int i = 0; i < maxPointerCount; ++i) {
         mProximityInfoStates[i].initInputParams(i, maxSpatialDistance, getProximityInfo(),
                 inputCodePoints, inputSize, inputXs, inputYs, times, pointerIds,
-                maxPointerCount == MAX_POINTER_COUNT_G
-                /* TODO: this is a hack. fix proximity info state */);
+                // Right now the line below is trying to figure out whether this is a gesture by
+                // looking at the pointer count and assuming whatever is above the cutoff is
+                // a gesture and whatever is below is type. This is hacky and incorrect, we
+                // should pass the correct information instead.
+                maxPointerCount == MAX_POINTER_COUNT_G,
+                getDictionaryStructurePolicy()->getHeaderStructurePolicy()->getLocale());
         mInputSize += mProximityInfoStates[i].size();
     }
 }
diff --git a/native/jni/src/suggest/core/session/dic_traverse_session.h b/native/jni/src/suggest/core/session/dic_traverse_session.h
index 5a51a112d..f5fcfddcd 100644
--- a/native/jni/src/suggest/core/session/dic_traverse_session.h
+++ b/native/jni/src/suggest/core/session/dic_traverse_session.h
@@ -20,16 +20,17 @@
 #include <vector>
 
 #include "defines.h"
+#include "dictionary/utils/multi_bigram_map.h"
 #include "jni.h"
 #include "suggest/core/dicnode/dic_nodes_cache.h"
-#include "suggest/core/dictionary/multi_bigram_map.h"
 #include "suggest/core/layout/proximity_info_state.h"
+#include "utils/int_array_view.h"
 
 namespace latinime {
 
 class Dictionary;
 class DictionaryStructureWithBufferPolicy;
-class PrevWordsInfo;
+class NgramContext;
 class ProximityInfo;
 class SuggestOptions;
 
@@ -50,20 +51,17 @@ class DicTraverseSession {
     }
 
     AK_FORCE_INLINE DicTraverseSession(JNIEnv *env, jstring localeStr, bool usesLargeCache)
-            : mProximityInfo(nullptr), mDictionary(nullptr), mSuggestOptions(nullptr),
-              mDicNodesCache(usesLargeCache), mMultiBigramMap(), mInputSize(0), mMaxPointerCount(1),
-              mMultiWordCostMultiplier(1.0f) {
+            : mPrevWordIdCount(0), mProximityInfo(nullptr), mDictionary(nullptr),
+              mSuggestOptions(nullptr), mDicNodesCache(usesLargeCache), mMultiBigramMap(),
+              mInputSize(0), mMaxPointerCount(1), mMultiWordCostMultiplier(1.0f) {
         // NOTE: mProximityInfoStates is an array of instances.
         // No need to initialize it explicitly here.
-        for (size_t i = 0; i < NELEMS(mPrevWordsPtNodePos); ++i) {
-            mPrevWordsPtNodePos[i] = NOT_A_DICT_POS;
-        }
     }
 
     // Non virtual inline destructor -- never inherit this class
     AK_FORCE_INLINE ~DicTraverseSession() {}
 
-    void init(const Dictionary *dictionary, const PrevWordsInfo *const prevWordsInfo,
+    void init(const Dictionary *dictionary, const NgramContext *const ngramContext,
             const SuggestOptions *const suggestOptions);
     // TODO: Remove and merge into init
     void setupForGetSuggestions(const ProximityInfo *pInfo, const int *inputCodePoints,
@@ -79,7 +77,9 @@ class DicTraverseSession {
     //--------------------
     const ProximityInfo *getProximityInfo() const { return mProximityInfo; }
     const SuggestOptions *getSuggestOptions() const { return mSuggestOptions; }
-    const int *getPrevWordsPtNodePos() const { return mPrevWordsPtNodePos; }
+    const WordIdArrayView getPrevWordIds() const {
+        return WordIdArrayView::fromArray(mPrevWordIdArray).limit(mPrevWordIdCount);
+    }
     DicNodesCache *getDicTraverseCache() { return &mDicNodesCache; }
     MultiBigramMap *getMultiBigramMap() { return &mMultiBigramMap; }
     const ProximityInfoState *getProximityInfoState(int id) const {
@@ -166,7 +166,8 @@ class DicTraverseSession {
             const int *const inputYs, const int *const times, const int *const pointerIds,
             const int inputSize, const float maxSpatialDistance, const int maxPointerCount);
 
-    int mPrevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    WordIdArray<MAX_PREV_WORD_COUNT_FOR_N_GRAM> mPrevWordIdArray;
+    size_t mPrevWordIdCount;
     const ProximityInfo *mProximityInfo;
     const Dictionary *mDictionary;
     const SuggestOptions *mSuggestOptions;
diff --git a/native/jni/src/suggest/core/session/prev_words_info.h b/native/jni/src/suggest/core/session/prev_words_info.h
deleted file mode 100644
index e44e876e9..000000000
--- a/native/jni/src/suggest/core/session/prev_words_info.h
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_PREV_WORDS_INFO_H
-#define LATINIME_PREV_WORDS_INFO_H
-
-#include "defines.h"
-#include "suggest/core/dictionary/binary_dictionary_bigrams_iterator.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
-#include "utils/char_utils.h"
-
-namespace latinime {
-
-// TODO: Support n-gram.
-class PrevWordsInfo {
- public:
-    // No prev word information.
-    PrevWordsInfo() {
-        clear();
-    }
-
-    PrevWordsInfo(PrevWordsInfo &&prevWordsInfo) {
-        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
-            mPrevWordCodePointCount[i] = prevWordsInfo.mPrevWordCodePointCount[i];
-            memmove(mPrevWordCodePoints[i], prevWordsInfo.mPrevWordCodePoints[i],
-                    sizeof(mPrevWordCodePoints[i][0]) * mPrevWordCodePointCount[i]);
-            mIsBeginningOfSentence[i] = prevWordsInfo.mIsBeginningOfSentence[i];
-        }
-    }
-
-    // Construct from previous words.
-    PrevWordsInfo(const int prevWordCodePoints[][MAX_WORD_LENGTH],
-            const int *const prevWordCodePointCount, const bool *const isBeginningOfSentence,
-            const size_t prevWordCount) {
-        clear();
-        for (size_t i = 0; i < std::min(NELEMS(mPrevWordCodePoints), prevWordCount); ++i) {
-            if (prevWordCodePointCount[i] < 0 || prevWordCodePointCount[i] > MAX_WORD_LENGTH) {
-                continue;
-            }
-            memmove(mPrevWordCodePoints[i], prevWordCodePoints[i],
-                    sizeof(mPrevWordCodePoints[i][0]) * prevWordCodePointCount[i]);
-            mPrevWordCodePointCount[i] = prevWordCodePointCount[i];
-            mIsBeginningOfSentence[i] = isBeginningOfSentence[i];
-        }
-    }
-
-    // Construct from a previous word.
-    PrevWordsInfo(const int *const prevWordCodePoints, const int prevWordCodePointCount,
-            const bool isBeginningOfSentence) {
-        clear();
-        if (prevWordCodePointCount > MAX_WORD_LENGTH || !prevWordCodePoints) {
-            return;
-        }
-        memmove(mPrevWordCodePoints[0], prevWordCodePoints,
-                sizeof(mPrevWordCodePoints[0][0]) * prevWordCodePointCount);
-        mPrevWordCodePointCount[0] = prevWordCodePointCount;
-        mIsBeginningOfSentence[0] = isBeginningOfSentence;
-    }
-
-    bool isValid() const {
-        if (mPrevWordCodePointCount[0] > 0) {
-            return true;
-        }
-        if (mIsBeginningOfSentence[0]) {
-            return true;
-        }
-        return false;
-    }
-
-    void getPrevWordsTerminalPtNodePos(
-            const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
-            int *const outPrevWordsTerminalPtNodePos, const bool tryLowerCaseSearch) const {
-        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
-            outPrevWordsTerminalPtNodePos[i] = getTerminalPtNodePosOfWord(dictStructurePolicy,
-                    mPrevWordCodePoints[i], mPrevWordCodePointCount[i],
-                    mIsBeginningOfSentence[i], tryLowerCaseSearch);
-        }
-    }
-
-    // n is 1-indexed.
-    const int *getNthPrevWordCodePoints(const int n) const {
-        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
-            return nullptr;
-        }
-        return mPrevWordCodePoints[n - 1];
-    }
-
-    // n is 1-indexed.
-    int getNthPrevWordCodePointCount(const int n) const {
-        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
-            return 0;
-        }
-        return mPrevWordCodePointCount[n - 1];
-    }
-
-    // n is 1-indexed.
-    bool isNthPrevWordBeginningOfSentence(const int n) const {
-        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
-            return false;
-        }
-        return mIsBeginningOfSentence[n - 1];
-    }
-
- private:
-    DISALLOW_COPY_AND_ASSIGN(PrevWordsInfo);
-
-    static int getTerminalPtNodePosOfWord(
-            const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
-            const int *const wordCodePoints, const int wordCodePointCount,
-            const bool isBeginningOfSentence, const bool tryLowerCaseSearch) {
-        if (!dictStructurePolicy || !wordCodePoints || wordCodePointCount > MAX_WORD_LENGTH) {
-            return NOT_A_DICT_POS;
-        }
-        int codePoints[MAX_WORD_LENGTH];
-        int codePointCount = wordCodePointCount;
-        memmove(codePoints, wordCodePoints, sizeof(int) * codePointCount);
-        if (isBeginningOfSentence) {
-            codePointCount = CharUtils::attachBeginningOfSentenceMarker(codePoints,
-                    codePointCount, MAX_WORD_LENGTH);
-            if (codePointCount <= 0) {
-                return NOT_A_DICT_POS;
-            }
-        }
-        const int wordPtNodePos = dictStructurePolicy->getTerminalPtNodePositionOfWord(
-                codePoints, codePointCount, false /* forceLowerCaseSearch */);
-        if (wordPtNodePos != NOT_A_DICT_POS || !tryLowerCaseSearch) {
-            // Return the position when when the word was found or doesn't try lower case
-            // search.
-            return wordPtNodePos;
-        }
-        // Check bigrams for lower-cased previous word if original was not found. Useful for
-        // auto-capitalized words like "The [current_word]".
-        return dictStructurePolicy->getTerminalPtNodePositionOfWord(
-                codePoints, codePointCount, true /* forceLowerCaseSearch */);
-    }
-
-    void clear() {
-        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
-            mPrevWordCodePointCount[i] = 0;
-            mIsBeginningOfSentence[i] = false;
-        }
-    }
-
-    int mPrevWordCodePoints[MAX_PREV_WORD_COUNT_FOR_N_GRAM][MAX_WORD_LENGTH];
-    int mPrevWordCodePointCount[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    bool mIsBeginningOfSentence[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-};
-} // namespace latinime
-#endif // LATINIME_PREV_WORDS_INFO_H
diff --git a/native/jni/src/suggest/core/suggest.cpp b/native/jni/src/suggest/core/suggest.cpp
index 0cd305f5a..52fa5a5db 100644
--- a/native/jni/src/suggest/core/suggest.cpp
+++ b/native/jni/src/suggest/core/suggest.cpp
@@ -16,17 +16,20 @@
 
 #include "suggest/core/suggest.h"
 
+#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
+#include "dictionary/property/word_attributes.h"
 #include "suggest/core/dicnode/dic_node.h"
 #include "suggest/core/dicnode/dic_node_priority_queue.h"
 #include "suggest/core/dicnode/dic_node_vector.h"
 #include "suggest/core/dictionary/dictionary.h"
 #include "suggest/core/dictionary/digraph_utils.h"
 #include "suggest/core/layout/proximity_info.h"
-#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
 #include "suggest/core/policy/traversal.h"
 #include "suggest/core/policy/weighting.h"
 #include "suggest/core/result/suggestions_output_utils.h"
 #include "suggest/core/session/dic_traverse_session.h"
+#include "suggest/core/suggest_options.h"
+#include "utils/profiler.h"
 
 namespace latinime {
 
@@ -44,10 +47,10 @@ const int Suggest::MIN_CONTINUOUS_SUGGESTION_INPUT_SIZE = 2;
  */
 void Suggest::getSuggestions(ProximityInfo *pInfo, void *traverseSession,
         int *inputXs, int *inputYs, int *times, int *pointerIds, int *inputCodePoints,
-        int inputSize, const float languageWeight,
+        int inputSize, const float weightOfLangModelVsSpatialModel,
         SuggestionResults *const outSuggestionResults) const {
-    PROF_OPEN;
-    PROF_START(0);
+    PROF_INIT;
+    PROF_TIMER_START(0);
     const float maxSpatialDistance = TRAVERSAL->getMaxSpatialDistance();
     DicTraverseSession *tSession = static_cast<DicTraverseSession *>(traverseSession);
     tSession->setupForGetSuggestions(pInfo, inputCodePoints, inputSize, inputXs, inputYs, times,
@@ -55,8 +58,8 @@ void Suggest::getSuggestions(ProximityInfo *pInfo, void *traverseSession,
     // TODO: Add the way to evaluate cache
 
     initializeSearch(tSession);
-    PROF_END(0);
-    PROF_START(1);
+    PROF_TIMER_END(0);
+    PROF_TIMER_START(1);
 
     // keep expanding search dicNodes until all have terminated.
     while (tSession->getDicTraverseCache()->activeSize() > 0) {
@@ -64,12 +67,11 @@ void Suggest::getSuggestions(ProximityInfo *pInfo, void *traverseSession,
         tSession->getDicTraverseCache()->advanceActiveDicNodes();
         tSession->getDicTraverseCache()->advanceInputIndex(inputSize);
     }
-    PROF_END(1);
-    PROF_START(2);
+    PROF_TIMER_END(1);
+    PROF_TIMER_START(2);
     SuggestionsOutputUtils::outputSuggestions(
-            SCORING, tSession, languageWeight, outSuggestionResults);
-    PROF_END(2);
-    PROF_CLOSE;
+            SCORING, tSession, weightOfLangModelVsSpatialModel, outSuggestionResults);
+    PROF_TIMER_END(2);
 }
 
 /**
@@ -87,12 +89,13 @@ void Suggest::initializeSearch(DicTraverseSession *traverseSession) const {
         traverseSession->getDicTraverseCache()->continueSearch();
     } else {
         // Restart recognition at the root.
-        traverseSession->resetCache(TRAVERSAL->getMaxCacheSize(traverseSession->getInputSize()),
+        traverseSession->resetCache(TRAVERSAL->getMaxCacheSize(traverseSession->getInputSize(),
+                traverseSession->getSuggestOptions()->weightForLocale()),
                 TRAVERSAL->getTerminalCacheSize());
         // Create a new dic node here
         DicNode rootNode;
         DicNodeUtils::initAsRoot(traverseSession->getDictionaryStructurePolicy(),
-                traverseSession->getPrevWordsPtNodePos(), &rootNode);
+                traverseSession->getPrevWordIds(), &rootNode);
         traverseSession->getDicTraverseCache()->copyPushActive(&rootNode);
     }
 }
@@ -157,8 +160,7 @@ void Suggest::expandCurrentDicNodes(DicTraverseSession *traverseSession) const {
             // TODO: Remove. Do not prune node here.
             const bool allowsErrorCorrections = TRAVERSAL->allowsErrorCorrections(&dicNode);
             // Process for handling space substitution (e.g., hevis => he is)
-            if (allowsErrorCorrections
-                    && TRAVERSAL->isSpaceSubstitutionTerminal(traverseSession, &dicNode)) {
+            if (TRAVERSAL->isSpaceSubstitutionTerminal(traverseSession, &dicNode)) {
                 createNextWordDicNode(traverseSession, &dicNode, true /* spaceSubstitution */);
             }
 
@@ -281,7 +283,6 @@ void Suggest::processDicNodeAsAdditionalProximityChar(DicTraverseSession *traver
     // not treat the node as a terminal. There is no need to pass the bigram map in these cases.
     Weighting::addCostAndForwardInputIndex(WEIGHTING, CT_ADDITIONAL_PROXIMITY,
             traverseSession, dicNode, childDicNode, 0 /* multiBigramMap */);
-    weightChildNode(traverseSession, childDicNode);
     processExpandedDicNode(traverseSession, childDicNode);
 }
 
@@ -289,7 +290,6 @@ void Suggest::processDicNodeAsSubstitution(DicTraverseSession *traverseSession,
         DicNode *dicNode, DicNode *childDicNode) const {
     Weighting::addCostAndForwardInputIndex(WEIGHTING, CT_SUBSTITUTION, traverseSession,
             dicNode, childDicNode, 0 /* multiBigramMap */);
-    weightChildNode(traverseSession, childDicNode);
     processExpandedDicNode(traverseSession, childDicNode);
 }
 
@@ -400,7 +400,7 @@ void Suggest::weightChildNode(DicTraverseSession *traverseSession, DicNode *dicN
     if (dicNode->isCompletion(inputSize)) {
         Weighting::addCostAndForwardInputIndex(WEIGHTING, CT_COMPLETION, traverseSession,
                 0 /* parentDicNode */, dicNode, 0 /* multiBigramMap */);
-    } else { // completion
+    } else {
         Weighting::addCostAndForwardInputIndex(WEIGHTING, CT_MATCH, traverseSession,
                 0 /* parentDicNode */, dicNode, 0 /* multiBigramMap */);
     }
@@ -412,7 +412,16 @@ void Suggest::weightChildNode(DicTraverseSession *traverseSession, DicNode *dicN
  */
 void Suggest::createNextWordDicNode(DicTraverseSession *traverseSession, DicNode *dicNode,
         const bool spaceSubstitution) const {
-    if (!TRAVERSAL->isGoodToTraverseNextWord(dicNode)) {
+    const WordAttributes wordAttributes =
+            traverseSession->getDictionaryStructurePolicy()->getWordAttributesInContext(
+                    dicNode->getPrevWordIds(), dicNode->getWordId(),
+                    traverseSession->getMultiBigramMap());
+    if (SuggestionsOutputUtils::shouldBlockWord(traverseSession->getSuggestOptions(),
+            dicNode, wordAttributes, false /* isLastWord */)) {
+        return;
+    }
+
+    if (!TRAVERSAL->isGoodToTraverseNextWord(dicNode, wordAttributes.getProbability())) {
         return;
     }
 
diff --git a/native/jni/src/suggest/core/suggest.h b/native/jni/src/suggest/core/suggest.h
index 788e0314b..65d5918cf 100644
--- a/native/jni/src/suggest/core/suggest.h
+++ b/native/jni/src/suggest/core/suggest.h
@@ -49,7 +49,8 @@ class Suggest : public SuggestInterface {
     AK_FORCE_INLINE virtual ~Suggest() {}
     void getSuggestions(ProximityInfo *pInfo, void *traverseSession, int *inputXs, int *inputYs,
             int *times, int *pointerIds, int *inputCodePoints, int inputSize,
-            const float languageWeight, SuggestionResults *const outSuggestionResults) const;
+            const float weightOfLangModelVsSpatialModel,
+            SuggestionResults *const outSuggestionResults) const;
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(Suggest);
diff --git a/native/jni/src/suggest/core/suggest_interface.h b/native/jni/src/suggest/core/suggest_interface.h
index a6e5aefae..a05aa9c80 100644
--- a/native/jni/src/suggest/core/suggest_interface.h
+++ b/native/jni/src/suggest/core/suggest_interface.h
@@ -28,7 +28,8 @@ class SuggestInterface {
  public:
     virtual void getSuggestions(ProximityInfo *pInfo, void *traverseSession, int *inputXs,
             int *inputYs, int *times, int *pointerIds, int *inputCodePoints, int inputSize,
-            const float languageWeight, SuggestionResults *const suggestionResults) const = 0;
+            const float weightOfLangModelVsSpatialModel,
+            SuggestionResults *const suggestionResults) const = 0;
     SuggestInterface() {}
     virtual ~SuggestInterface() {}
  private:
diff --git a/native/jni/src/suggest/core/suggest_options.h b/native/jni/src/suggest/core/suggest_options.h
index d456680dd..4d331292b 100644
--- a/native/jni/src/suggest/core/suggest_options.h
+++ b/native/jni/src/suggest/core/suggest_options.h
@@ -42,6 +42,12 @@ class SuggestOptions{
         return getBoolOption(SPACE_AWARE_GESTURE_ENABLED);
     }
 
+    AK_FORCE_INLINE float weightForLocale() const {
+        // The weight is in thousands and we want the real value, so we divide by 1000.
+        // NativeSuggestOptions#setWeightForLocale does the opposite processing in Java.
+        return static_cast<float>(getIntOption(WEIGHT_FOR_LOCALE_IN_THOUSANDS)) / 1000.0f;
+    }
+
     AK_FORCE_INLINE bool getAdditionalFeaturesBoolOption(const int key) const {
         return getBoolOption(key + ADDITIONAL_FEATURES_OPTIONS);
     }
@@ -55,9 +61,10 @@ class SuggestOptions{
     static const int USE_FULL_EDIT_DISTANCE = 1;
     static const int BLOCK_OFFENSIVE_WORDS = 2;
     static const int SPACE_AWARE_GESTURE_ENABLED = 3;
+    static const int WEIGHT_FOR_LOCALE_IN_THOUSANDS = 4;
     // Additional features options are stored after the other options and used as setting values of
     // experimental features.
-    static const int ADDITIONAL_FEATURES_OPTIONS = 4;
+    static const int ADDITIONAL_FEATURES_OPTIONS = 5;
 
     const int *const mOptions;
     const int mLength;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp
deleted file mode 100644
index 08dc107ab..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp
+++ /dev/null
@@ -1,282 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h"
-
-#include "suggest/core/dictionary/property/bigram_property.h"
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
-
-namespace latinime {
-
-void Ver4BigramListPolicy::getNextBigram(int *const outBigramPos, int *const outProbability,
-        bool *const outHasNext, int *const bigramEntryPos) const {
-    const BigramEntry bigramEntry =
-            mBigramDictContent->getBigramEntryAndAdvancePosition(bigramEntryPos);
-    if (outBigramPos) {
-        // Lookup target PtNode position.
-        *outBigramPos = mTerminalPositionLookupTable->getTerminalPtNodePosition(
-                bigramEntry.getTargetTerminalId());
-    }
-    if (outProbability) {
-        if (bigramEntry.hasHistoricalInfo()) {
-            *outProbability =
-                    ForgettingCurveUtils::decodeProbability(bigramEntry.getHistoricalInfo(),
-                            mHeaderPolicy);
-        } else {
-            *outProbability = bigramEntry.getProbability();
-        }
-    }
-    if (outHasNext) {
-        *outHasNext = bigramEntry.hasNext();
-    }
-}
-
-bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTargetTerminalId,
-        const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) {
-    // 1. The word has no bigrams yet.
-    // 2. The word has bigrams, and there is the target in the list.
-    // 3. The word has bigrams, and there is an invalid entry that can be reclaimed.
-    // 4. The word has bigrams. We have to append new bigram entry to the list.
-    // 5. Same as 4, but the list is the last entry of the content file.
-    if (outAddedNewEntry) {
-        *outAddedNewEntry = false;
-    }
-    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
-    if (bigramListPos == NOT_A_DICT_POS) {
-        // Case 1. PtNode that doesn't have a bigram list.
-        // Create new bigram list.
-        if (!mBigramDictContent->createNewBigramList(terminalId)) {
-            return false;
-        }
-        const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
-                newTargetTerminalId);
-        const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(&newBigramEntry,
-                bigramProperty);
-        // Write an entry.
-        int writingPos =  mBigramDictContent->getBigramListHeadPos(terminalId);
-        if (!mBigramDictContent->writeBigramEntryAndAdvancePosition(&bigramEntryToWrite,
-                &writingPos)) {
-            AKLOGE("Cannot write bigram entry. pos: %d.", writingPos);
-            return false;
-        }
-        if (!mBigramDictContent->writeTerminator(writingPos)) {
-            AKLOGE("Cannot write bigram list terminator. pos: %d.", writingPos);
-            return false;
-        }
-        if (outAddedNewEntry) {
-            *outAddedNewEntry = true;
-        }
-        return true;
-    }
-
-    int tailEntryPos = NOT_A_DICT_POS;
-    const int entryPosToUpdate = getEntryPosToUpdate(newTargetTerminalId, bigramListPos,
-            &tailEntryPos);
-    if (entryPosToUpdate == NOT_A_DICT_POS) {
-        // Case 4, 5. Add new entry to the bigram list.
-        const int contentTailPos = mBigramDictContent->getContentTailPos();
-        // If the tail entry is at the tail of content buffer, the new entry can be written without
-        // link (Case 5).
-        const bool canAppendEntry =
-                contentTailPos == tailEntryPos + mBigramDictContent->getBigramEntrySize();
-        const int newEntryPos = canAppendEntry ? tailEntryPos : contentTailPos;
-        int writingPos = newEntryPos;
-        // Write new entry at the tail position of the bigram content.
-        const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
-                newTargetTerminalId);
-        const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-                &newBigramEntry, bigramProperty);
-        if (!mBigramDictContent->writeBigramEntryAndAdvancePosition(&bigramEntryToWrite,
-                &writingPos)) {
-            AKLOGE("Cannot write bigram entry. pos: %d.", writingPos);
-            return false;
-        }
-        if (!mBigramDictContent->writeTerminator(writingPos)) {
-            AKLOGE("Cannot write bigram list terminator. pos: %d.", writingPos);
-            return false;
-        }
-        if (!canAppendEntry) {
-            // Update link of the current tail entry.
-            if (!mBigramDictContent->writeLink(newEntryPos, tailEntryPos)) {
-                AKLOGE("Cannot update bigram entry link. pos: %d, linked entry pos: %d.",
-                        tailEntryPos, newEntryPos);
-                return false;
-            }
-        }
-        if (outAddedNewEntry) {
-            *outAddedNewEntry = true;
-        }
-        return true;
-    }
-
-    // Case 2. Overwrite the existing entry. Case 3. Reclaim and reuse the existing invalid entry.
-    const BigramEntry originalBigramEntry = mBigramDictContent->getBigramEntry(entryPosToUpdate);
-    if (!originalBigramEntry.isValid()) {
-        // Case 3. Reuse the existing invalid entry. outAddedNewEntry is false when an existing
-        // entry is updated.
-        if (outAddedNewEntry) {
-            *outAddedNewEntry = true;
-        }
-    }
-    const BigramEntry updatedBigramEntry =
-            originalBigramEntry.updateTargetTerminalIdAndGetEntry(newTargetTerminalId);
-    const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
-            &updatedBigramEntry, bigramProperty);
-    return mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, entryPosToUpdate);
-}
-
-bool Ver4BigramListPolicy::removeEntry(const int terminalId, const int targetTerminalId) {
-    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
-    if (bigramListPos == NOT_A_DICT_POS) {
-        // Bigram list doesn't exist.
-        return false;
-    }
-    const int entryPosToUpdate = getEntryPosToUpdate(targetTerminalId, bigramListPos,
-            nullptr /* outTailEntryPos */);
-    if (entryPosToUpdate == NOT_A_DICT_POS) {
-        // Bigram entry doesn't exist.
-        return false;
-    }
-    const BigramEntry bigramEntry = mBigramDictContent->getBigramEntry(entryPosToUpdate);
-    if (targetTerminalId != bigramEntry.getTargetTerminalId()) {
-        // Bigram entry doesn't exist.
-        return false;
-    }
-    // Remove bigram entry by marking it as invalid entry and overwriting the original entry.
-    const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
-    return mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPosToUpdate);
-}
-
-bool Ver4BigramListPolicy::updateAllBigramEntriesAndDeleteUselessEntries(const int terminalId,
-        int *const outBigramCount) {
-    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
-    if (bigramListPos == NOT_A_DICT_POS) {
-        // Bigram list doesn't exist.
-        return true;
-    }
-    bool hasNext = true;
-    int readingPos = bigramListPos;
-    while (hasNext) {
-        const BigramEntry bigramEntry =
-                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-        const int entryPos = readingPos - mBigramDictContent->getBigramEntrySize();
-        hasNext = bigramEntry.hasNext();
-        if (!bigramEntry.isValid()) {
-            continue;
-        }
-        const int targetPtNodePos = mTerminalPositionLookupTable->getTerminalPtNodePosition(
-                bigramEntry.getTargetTerminalId());
-        if (targetPtNodePos == NOT_A_DICT_POS) {
-            // Invalidate bigram entry.
-            const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
-            if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
-                return false;
-            }
-        } else if (bigramEntry.hasHistoricalInfo()) {
-            const HistoricalInfo historicalInfo = ForgettingCurveUtils::createHistoricalInfoToSave(
-                    bigramEntry.getHistoricalInfo(), mHeaderPolicy);
-            if (ForgettingCurveUtils::needsToKeep(&historicalInfo, mHeaderPolicy)) {
-                const BigramEntry updatedBigramEntry =
-                        bigramEntry.updateHistoricalInfoAndGetEntry(&historicalInfo);
-                if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
-                    return false;
-                }
-                *outBigramCount += 1;
-            } else {
-                // Remove entry.
-                const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
-                if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
-                    return false;
-                }
-            }
-        } else {
-            *outBigramCount += 1;
-        }
-    }
-    return true;
-}
-
-int Ver4BigramListPolicy::getBigramEntryConut(const int terminalId) {
-    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
-    if (bigramListPos == NOT_A_DICT_POS) {
-        // Bigram list doesn't exist.
-        return 0;
-    }
-    int bigramCount = 0;
-    bool hasNext = true;
-    int readingPos = bigramListPos;
-    while (hasNext) {
-        const BigramEntry bigramEntry =
-                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-        hasNext = bigramEntry.hasNext();
-        if (bigramEntry.isValid()) {
-            bigramCount++;
-        }
-    }
-    return bigramCount;
-}
-
-int Ver4BigramListPolicy::getEntryPosToUpdate(const int targetTerminalIdToFind,
-        const int bigramListPos, int *const outTailEntryPos) const {
-    if (outTailEntryPos) {
-        *outTailEntryPos = NOT_A_DICT_POS;
-    }
-    int invalidEntryPos = NOT_A_DICT_POS;
-    int readingPos = bigramListPos;
-    while (true) {
-        const BigramEntry bigramEntry =
-                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-        const int entryPos = readingPos - mBigramDictContent->getBigramEntrySize();
-        if (!bigramEntry.hasNext()) {
-            if (outTailEntryPos) {
-                *outTailEntryPos = entryPos;
-            }
-            break;
-        }
-        if (bigramEntry.getTargetTerminalId() == targetTerminalIdToFind) {
-            // Entry with same target is found.
-            return entryPos;
-        } else if (!bigramEntry.isValid()) {
-            // Invalid entry that can be reused is found.
-            invalidEntryPos = entryPos;
-        }
-    }
-    return invalidEntryPos;
-}
-
-const BigramEntry Ver4BigramListPolicy::createUpdatedBigramEntryFrom(
-        const BigramEntry *const originalBigramEntry,
-        const BigramProperty *const bigramProperty) const {
-    // TODO: Consolidate historical info and probability.
-    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
-        const HistoricalInfo historicalInfoForUpdate(bigramProperty->getTimestamp(),
-                bigramProperty->getLevel(), bigramProperty->getCount());
-        const HistoricalInfo updatedHistoricalInfo =
-                ForgettingCurveUtils::createUpdatedHistoricalInfo(
-                        originalBigramEntry->getHistoricalInfo(), bigramProperty->getProbability(),
-                        &historicalInfoForUpdate, mHeaderPolicy);
-        return originalBigramEntry->updateHistoricalInfoAndGetEntry(&updatedHistoricalInfo);
-    } else {
-        return originalBigramEntry->updateProbabilityAndGetEntry(bigramProperty->getProbability());
-    }
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h
deleted file mode 100644
index 4b3bb3725..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_VER4_BIGRAM_LIST_POLICY_H
-#define LATINIME_VER4_BIGRAM_LIST_POLICY_H
-
-#include "defines.h"
-#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h"
-
-namespace latinime {
-
-class BigramDictContent;
-class BigramProperty;
-class HeaderPolicy;
-class TerminalPositionLookupTable;
-
-class Ver4BigramListPolicy : public DictionaryBigramsStructurePolicy {
- public:
-    Ver4BigramListPolicy(BigramDictContent *const bigramDictContent,
-            const TerminalPositionLookupTable *const terminalPositionLookupTable,
-            const HeaderPolicy *const headerPolicy)
-            : mBigramDictContent(bigramDictContent),
-              mTerminalPositionLookupTable(terminalPositionLookupTable),
-              mHeaderPolicy(headerPolicy) {}
-
-    void getNextBigram(int *const outBigramPos, int *const outProbability,
-            bool *const outHasNext, int *const bigramEntryPos) const;
-
-    bool skipAllBigrams(int *const pos) const {
-        // Do nothing because we don't need to skip bigram lists in ver4 dictionaries.
-        return true;
-    }
-
-    bool addNewEntry(const int terminalId, const int newTargetTerminalId,
-            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
-
-    bool removeEntry(const int terminalId, const int targetTerminalId);
-
-    bool updateAllBigramEntriesAndDeleteUselessEntries(const int terminalId,
-            int *const outBigramCount);
-
-    int getBigramEntryConut(const int terminalId);
-
- private:
-    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4BigramListPolicy);
-
-    int getEntryPosToUpdate(const int targetTerminalIdToFind, const int bigramListPos,
-            int *const outTailEntryPos) const;
-
-    const BigramEntry createUpdatedBigramEntryFrom(const BigramEntry *const originalBigramEntry,
-            const BigramProperty *const bigramProperty) const;
-
-    BigramDictContent *const mBigramDictContent;
-    const TerminalPositionLookupTable *const mTerminalPositionLookupTable;
-    const HeaderPolicy *const mHeaderPolicy;
-};
-} // namespace latinime
-#endif /* LATINIME_VER4_BIGRAM_LIST_POLICY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.cpp
deleted file mode 100644
index d7e1952b5..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.cpp
+++ /dev/null
@@ -1,219 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h"
-
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-
-namespace latinime {
-
-const int BigramDictContent::INVALID_LINKED_ENTRY_POS = Ver4DictConstants::NOT_A_TERMINAL_ID;
-
-const BigramEntry BigramDictContent::getBigramEntryAndAdvancePosition(
-        int *const bigramEntryPos) const {
-    const BufferWithExtendableBuffer *const bigramListBuffer = getContentBuffer();
-    const int bigramEntryTailPos = (*bigramEntryPos) + getBigramEntrySize();
-    if (*bigramEntryPos < 0 || bigramEntryTailPos > bigramListBuffer->getTailPosition()) {
-        AKLOGE("Invalid bigram entry position. bigramEntryPos: %d, bigramEntryTailPos: %d, "
-                "bufSize: %d", *bigramEntryPos, bigramEntryTailPos,
-                        bigramListBuffer->getTailPosition());
-        ASSERT(false);
-        return BigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
-                Ver4DictConstants::NOT_A_TERMINAL_ID);
-    }
-    const int bigramFlags = bigramListBuffer->readUintAndAdvancePosition(
-            Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE, bigramEntryPos);
-    const bool isLink = (bigramFlags & Ver4DictConstants::BIGRAM_IS_LINK_MASK) != 0;
-    int probability = NOT_A_PROBABILITY;
-    int timestamp = NOT_A_TIMESTAMP;
-    int level = 0;
-    int count = 0;
-    if (mHasHistoricalInfo) {
-        timestamp = bigramListBuffer->readUintAndAdvancePosition(
-                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, bigramEntryPos);
-        level = bigramListBuffer->readUintAndAdvancePosition(
-                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, bigramEntryPos);
-        count = bigramListBuffer->readUintAndAdvancePosition(
-                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, bigramEntryPos);
-    } else {
-        probability = bigramListBuffer->readUintAndAdvancePosition(
-                Ver4DictConstants::PROBABILITY_SIZE, bigramEntryPos);
-    }
-    const int encodedTargetTerminalId = bigramListBuffer->readUintAndAdvancePosition(
-            Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE, bigramEntryPos);
-    const int targetTerminalId =
-            (encodedTargetTerminalId == Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID) ?
-                    Ver4DictConstants::NOT_A_TERMINAL_ID : encodedTargetTerminalId;
-    if (isLink) {
-        const int linkedEntryPos = targetTerminalId;
-        if (linkedEntryPos == INVALID_LINKED_ENTRY_POS) {
-            // Bigram list terminator is found.
-            return BigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
-                    Ver4DictConstants::NOT_A_TERMINAL_ID);
-        }
-        *bigramEntryPos = linkedEntryPos;
-        return getBigramEntryAndAdvancePosition(bigramEntryPos);
-    }
-    // hasNext is always true because we should continue to read the next entry until the terminator
-    // is found.
-    if (mHasHistoricalInfo) {
-        const HistoricalInfo historicalInfo(timestamp, level, count);
-        return BigramEntry(true /* hasNext */, probability, &historicalInfo, targetTerminalId);
-    } else {
-        return BigramEntry(true /* hasNext */, probability, targetTerminalId);
-    }
-}
-
-bool BigramDictContent::writeBigramEntryAndAdvancePosition(
-        const BigramEntry *const bigramEntryToWrite, int *const entryWritingPos) {
-    return writeBigramEntryAttributesAndAdvancePosition(false /* isLink */,
-            bigramEntryToWrite->getProbability(), bigramEntryToWrite->getTargetTerminalId(),
-            bigramEntryToWrite->getHistoricalInfo()->getTimeStamp(),
-            bigramEntryToWrite->getHistoricalInfo()->getLevel(),
-            bigramEntryToWrite->getHistoricalInfo()->getCount(),
-            entryWritingPos);
-}
-
-bool BigramDictContent::writeBigramEntryAttributesAndAdvancePosition(
-        const bool isLink, const int probability, const int targetTerminalId,
-        const int timestamp, const int level, const int count, int *const entryWritingPos) {
-    BufferWithExtendableBuffer *const bigramListBuffer = getWritableContentBuffer();
-    const int bigramFlags = isLink ? Ver4DictConstants::BIGRAM_IS_LINK_MASK : 0;
-    if (!bigramListBuffer->writeUintAndAdvancePosition(bigramFlags,
-            Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE, entryWritingPos)) {
-        AKLOGE("Cannot write bigram flags. pos: %d, flags: %x", *entryWritingPos, bigramFlags);
-        return false;
-    }
-    if (mHasHistoricalInfo) {
-        if (!bigramListBuffer->writeUintAndAdvancePosition(timestamp,
-                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, entryWritingPos)) {
-            AKLOGE("Cannot write bigram timestamps. pos: %d, timestamp: %d", *entryWritingPos,
-                    timestamp);
-            return false;
-        }
-        if (!bigramListBuffer->writeUintAndAdvancePosition(level,
-                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, entryWritingPos)) {
-            AKLOGE("Cannot write bigram level. pos: %d, level: %d", *entryWritingPos,
-                    level);
-            return false;
-        }
-        if (!bigramListBuffer->writeUintAndAdvancePosition(count,
-                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, entryWritingPos)) {
-            AKLOGE("Cannot write bigram count. pos: %d, count: %d", *entryWritingPos,
-                    count);
-            return false;
-        }
-    } else {
-        if (!bigramListBuffer->writeUintAndAdvancePosition(probability,
-                Ver4DictConstants::PROBABILITY_SIZE, entryWritingPos)) {
-            AKLOGE("Cannot write bigram probability. pos: %d, probability: %d", *entryWritingPos,
-                    probability);
-            return false;
-        }
-    }
-    const int targetTerminalIdToWrite = (targetTerminalId == Ver4DictConstants::NOT_A_TERMINAL_ID) ?
-            Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID : targetTerminalId;
-    if (!bigramListBuffer->writeUintAndAdvancePosition(targetTerminalIdToWrite,
-            Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE, entryWritingPos)) {
-        AKLOGE("Cannot write bigram target terminal id. pos: %d, target terminal id: %d",
-                *entryWritingPos, targetTerminalId);
-        return false;
-    }
-    return true;
-}
-
-bool BigramDictContent::writeLink(const int linkedEntryPos, const int writingPos) {
-    const int targetTerminalId = linkedEntryPos;
-    int pos = writingPos;
-    return writeBigramEntryAttributesAndAdvancePosition(true /* isLink */,
-            NOT_A_PROBABILITY /* probability */, targetTerminalId, NOT_A_TIMESTAMP, 0 /* level */,
-            0 /* count */, &pos);
-}
-
-bool BigramDictContent::runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-        const BigramDictContent *const originalBigramDictContent,
-        int *const outBigramEntryCount) {
-    for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
-            it != terminalIdMap->end(); ++it) {
-        const int originalBigramListPos =
-                originalBigramDictContent->getBigramListHeadPos(it->first);
-        if (originalBigramListPos == NOT_A_DICT_POS) {
-            // This terminal does not have a bigram list.
-            continue;
-        }
-        const int bigramListPos = getContentBuffer()->getTailPosition();
-        int bigramEntryCount = 0;
-        // Copy bigram list with GC from original content.
-        if (!runGCBigramList(originalBigramListPos, originalBigramDictContent, bigramListPos,
-                terminalIdMap, &bigramEntryCount)) {
-            AKLOGE("Cannot complete GC for the bigram list. original pos: %d, pos: %d",
-                    originalBigramListPos, bigramListPos);
-            return false;
-        }
-        if (bigramEntryCount == 0) {
-            // All bigram entries are useless. This terminal does not have a bigram list.
-            continue;
-        }
-        *outBigramEntryCount += bigramEntryCount;
-        // Set bigram list position to the lookup table.
-        if (!getUpdatableAddressLookupTable()->set(it->second, bigramListPos)) {
-            AKLOGE("Cannot set bigram list position. terminal id: %d, pos: %d",
-                    it->second, bigramListPos);
-            return false;
-        }
-    }
-    return true;
-}
-
-// Returns whether GC for the bigram list was succeeded or not.
-bool BigramDictContent::runGCBigramList(const int bigramListPos,
-        const BigramDictContent *const sourceBigramDictContent, const int toPos,
-        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-        int *const outEntryCount) {
-    bool hasNext = true;
-    int readingPos = bigramListPos;
-    int writingPos = toPos;
-    while (hasNext) {
-        const BigramEntry originalBigramEntry =
-                sourceBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-        hasNext = originalBigramEntry.hasNext();
-        if (!originalBigramEntry.isValid()) {
-            continue;
-        }
-        TerminalPositionLookupTable::TerminalIdMap::const_iterator it =
-                terminalIdMap->find(originalBigramEntry.getTargetTerminalId());
-        if (it == terminalIdMap->end()) {
-            // Target word has been removed.
-            continue;
-        }
-        const BigramEntry updatedBigramEntry =
-                originalBigramEntry.updateTargetTerminalIdAndGetEntry(it->second);
-        if (!writeBigramEntryAndAdvancePosition(&updatedBigramEntry, &writingPos)) {
-            AKLOGE("Cannot write bigram entry to run GC. pos: %d", writingPos);
-            return false;
-        }
-        *outEntryCount += 1;
-    }
-    if (*outEntryCount > 0) {
-        if (!writeTerminator(writingPos)) {
-            AKLOGE("Cannot write terminator to run GC. pos: %d", writingPos);
-            return false;
-        }
-    }
-    return true;
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h
deleted file mode 100644
index 361dd2c74..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h
+++ /dev/null
@@ -1,128 +0,0 @@
-/*
- * Copyright (C) 2013, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_BIGRAM_DICT_CONTENT_H
-#define LATINIME_BIGRAM_DICT_CONTENT_H
-
-#include <cstdint>
-#include <cstdio>
-
-#include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-
-namespace latinime {
-
-class BigramDictContent : public SparseTableDictContent {
- public:
-    BigramDictContent(uint8_t *const *buffers, const int *bufferSizes, const bool hasHistoricalInfo)
-            : SparseTableDictContent(buffers, bufferSizes,
-                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE,
-                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE),
-              mHasHistoricalInfo(hasHistoricalInfo) {}
-
-    BigramDictContent(const bool hasHistoricalInfo)
-            : SparseTableDictContent(Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE,
-                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE),
-              mHasHistoricalInfo(hasHistoricalInfo) {}
-
-    int getContentTailPos() const {
-        return getContentBuffer()->getTailPosition();
-    }
-
-    const BigramEntry getBigramEntry(const int bigramEntryPos) const {
-        int readingPos = bigramEntryPos;
-        return getBigramEntryAndAdvancePosition(&readingPos);
-    }
-
-    const BigramEntry getBigramEntryAndAdvancePosition(int *const bigramEntryPos) const;
-
-    // Returns head position of bigram list for a PtNode specified by terminalId.
-    int getBigramListHeadPos(const int terminalId) const {
-        const SparseTable *const addressLookupTable = getAddressLookupTable();
-        if (!addressLookupTable->contains(terminalId)) {
-            return NOT_A_DICT_POS;
-        }
-        return addressLookupTable->get(terminalId);
-    }
-
-    bool writeBigramEntryAtTail(const BigramEntry *const bigramEntryToWrite) {
-        int writingPos = getContentBuffer()->getTailPosition();
-        return writeBigramEntryAndAdvancePosition(bigramEntryToWrite, &writingPos);
-    }
-
-    bool writeBigramEntry(const BigramEntry *const bigramEntryToWrite, const int entryWritingPos) {
-        int writingPos = entryWritingPos;
-        return writeBigramEntryAndAdvancePosition(bigramEntryToWrite, &writingPos);
-    }
-
-    bool writeBigramEntryAndAdvancePosition(const BigramEntry *const bigramEntryToWrite,
-            int *const entryWritingPos);
-
-    bool writeTerminator(const int writingPos) {
-        // Terminator is a link to the invalid position.
-        return writeLink(INVALID_LINKED_ENTRY_POS, writingPos);
-    }
-
-    bool writeLink(const int linkedPos, const int writingPos);
-
-    bool createNewBigramList(const int terminalId) {
-        const int bigramListPos = getContentBuffer()->getTailPosition();
-        return getUpdatableAddressLookupTable()->set(terminalId, bigramListPos);
-    }
-
-    bool flushToFile(FILE *const file) const {
-        return flush(file);
-    }
-
-    bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-            const BigramDictContent *const originalBigramDictContent,
-            int *const outBigramEntryCount);
-
-    int getBigramEntrySize() const {
-        if (mHasHistoricalInfo) {
-            return Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE
-                    + Ver4DictConstants::TIME_STAMP_FIELD_SIZE
-                    + Ver4DictConstants::WORD_LEVEL_FIELD_SIZE
-                    + Ver4DictConstants::WORD_COUNT_FIELD_SIZE
-                    + Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE;
-        } else {
-            return Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE
-                    + Ver4DictConstants::PROBABILITY_SIZE
-                    + Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE;
-        }
-    }
-
- private:
-    DISALLOW_COPY_AND_ASSIGN(BigramDictContent);
-
-    static const int INVALID_LINKED_ENTRY_POS;
-
-    bool writeBigramEntryAttributesAndAdvancePosition(
-            const bool isLink, const int probability, const int targetTerminalId,
-            const int timestamp, const int level, const int count, int *const entryWritingPos);
-
-    bool runGCBigramList(const int bigramListPos,
-            const BigramDictContent *const sourceBigramDictContent, const int toPos,
-            const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-            int *const outEntryCount);
-
-    bool mHasHistoricalInfo;
-};
-} // namespace latinime
-#endif /* LATINIME_BIGRAM_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h
deleted file mode 100644
index 2b0cbd93b..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * Copyright (C) 2013, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_BIGRAM_ENTRY_H
-#define LATINIME_BIGRAM_ENTRY_H
-
-#include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/historical_info.h"
-
-namespace latinime {
-
-class BigramEntry {
- public:
-    BigramEntry(const BigramEntry& bigramEntry)
-            : mHasNext(bigramEntry.mHasNext), mProbability(bigramEntry.mProbability),
-              mHistoricalInfo(), mTargetTerminalId(bigramEntry.mTargetTerminalId) {}
-
-    // Entry with historical information.
-    BigramEntry(const bool hasNext, const int probability, const int targetTerminalId)
-            : mHasNext(hasNext), mProbability(probability), mHistoricalInfo(),
-              mTargetTerminalId(targetTerminalId) {}
-
-    // Entry with historical information.
-    BigramEntry(const bool hasNext, const int probability,
-            const HistoricalInfo *const historicalInfo, const int targetTerminalId)
-            : mHasNext(hasNext), mProbability(probability), mHistoricalInfo(*historicalInfo),
-              mTargetTerminalId(targetTerminalId) {}
-
-    const BigramEntry getInvalidatedEntry() const {
-        return updateTargetTerminalIdAndGetEntry(Ver4DictConstants::NOT_A_TERMINAL_ID);
-    }
-
-    const BigramEntry updateHasNextAndGetEntry(const bool hasNext) const {
-        return BigramEntry(hasNext, mProbability, &mHistoricalInfo, mTargetTerminalId);
-    }
-
-    const BigramEntry updateTargetTerminalIdAndGetEntry(const int newTargetTerminalId) const {
-        return BigramEntry(mHasNext, mProbability, &mHistoricalInfo, newTargetTerminalId);
-    }
-
-    const BigramEntry updateProbabilityAndGetEntry(const int probability) const {
-        return BigramEntry(mHasNext, probability, &mHistoricalInfo, mTargetTerminalId);
-    }
-
-    const BigramEntry updateHistoricalInfoAndGetEntry(
-            const HistoricalInfo *const historicalInfo) const {
-        return BigramEntry(mHasNext, mProbability, historicalInfo, mTargetTerminalId);
-    }
-
-    bool isValid() const {
-        return mTargetTerminalId != Ver4DictConstants::NOT_A_TERMINAL_ID;
-    }
-
-    bool hasNext() const {
-        return mHasNext;
-    }
-
-    int getProbability() const {
-        return mProbability;
-    }
-
-    bool hasHistoricalInfo() const {
-        return mHistoricalInfo.isValid();
-    }
-
-    const HistoricalInfo *getHistoricalInfo() const {
-        return &mHistoricalInfo;
-    }
-
-    int getTargetTerminalId() const {
-        return mTargetTerminalId;
-    }
-
- private:
-    // Copy constructor is public to use this class as a type of return value.
-    DISALLOW_DEFAULT_CONSTRUCTOR(BigramEntry);
-    DISALLOW_ASSIGNMENT_OPERATOR(BigramEntry);
-
-    const bool mHasNext;
-    const int mProbability;
-    const HistoricalInfo mHistoricalInfo;
-    const int mTargetTerminalId;
-};
-} // namespace latinime
-#endif /* LATINIME_BIGRAM_ENTRY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.cpp
deleted file mode 100644
index 5dc91ba10..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.cpp
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * Copyright (C) 2014, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h"
-
-namespace latinime {
-
-bool LanguageModelDictContent::save(FILE *const file) const {
-    return mTrieMap.save(file);
-}
-
-bool LanguageModelDictContent::runGC(
-        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-        const LanguageModelDictContent *const originalContent,
-        int *const outNgramCount) {
-    return runGCInner(terminalIdMap, originalContent->mTrieMap.getEntriesInRootLevel(),
-            0 /* nextLevelBitmapEntryIndex */, outNgramCount);
-}
-
-ProbabilityEntry LanguageModelDictContent::getNgramProbabilityEntry(
-        const WordIdArrayView prevWordIds, const int wordId) const {
-    const int bitmapEntryIndex = getBitmapEntryIndex(prevWordIds);
-    if (bitmapEntryIndex == TrieMap::INVALID_INDEX) {
-        return ProbabilityEntry();
-    }
-    const TrieMap::Result result = mTrieMap.get(wordId, bitmapEntryIndex);
-    if (!result.mIsValid) {
-        // Not found.
-        return ProbabilityEntry();
-    }
-    return ProbabilityEntry::decode(result.mValue, mHasHistoricalInfo);
-}
-
-bool LanguageModelDictContent::setNgramProbabilityEntry(const WordIdArrayView prevWordIds,
-        const int terminalId, const ProbabilityEntry *const probabilityEntry) {
-    const int bitmapEntryIndex = getBitmapEntryIndex(prevWordIds);
-    if (bitmapEntryIndex == TrieMap::INVALID_INDEX) {
-        return false;
-    }
-    return mTrieMap.put(terminalId, probabilityEntry->encode(mHasHistoricalInfo), bitmapEntryIndex);
-}
-
-bool LanguageModelDictContent::runGCInner(
-        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-        const TrieMap::TrieMapRange trieMapRange,
-        const int nextLevelBitmapEntryIndex, int *const outNgramCount) {
-    for (auto &entry : trieMapRange) {
-        const auto it = terminalIdMap->find(entry.key());
-        if (it == terminalIdMap->end() || it->second == Ver4DictConstants::NOT_A_TERMINAL_ID) {
-            // The word has been removed.
-            continue;
-        }
-        if (!mTrieMap.put(it->second, entry.value(), nextLevelBitmapEntryIndex)) {
-            return false;
-        }
-        if (outNgramCount) {
-            *outNgramCount += 1;
-        }
-        if (entry.hasNextLevelMap()) {
-            if (!runGCInner(terminalIdMap, entry.getEntriesInNextLevel(),
-                    mTrieMap.getNextLevelBitmapEntryIndex(it->second, nextLevelBitmapEntryIndex),
-                    outNgramCount)) {
-                return false;
-            }
-        }
-    }
-    return true;
-}
-
-int LanguageModelDictContent::getBitmapEntryIndex(const WordIdArrayView prevWordIds) const {
-    int bitmapEntryIndex = mTrieMap.getRootBitmapEntryIndex();
-    for (const int wordId : prevWordIds) {
-        const TrieMap::Result result = mTrieMap.get(wordId, bitmapEntryIndex);
-        if (!result.mIsValid) {
-            return TrieMap::INVALID_INDEX;
-        }
-        bitmapEntryIndex = result.mNextLevelBitmapEntryIndex;
-    }
-    return bitmapEntryIndex;
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h
deleted file mode 100644
index 18f2e0170..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/content/language_model_dict_content.h
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * Copyright (C) 2014, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H
-#define LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H
-
-#include <cstdio>
-
-#include "defines.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h"
-#include "suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/utils/trie_map.h"
-#include "utils/byte_array_view.h"
-#include "utils/int_array_view.h"
-
-namespace latinime {
-
-/**
- * Class representing language model.
- *
- * This class provides methods to get and store unigram/n-gram probability information and flags.
- */
-class LanguageModelDictContent {
- public:
-    LanguageModelDictContent(const ReadWriteByteArrayView trieMapBuffer,
-            const bool hasHistoricalInfo)
-            : mTrieMap(trieMapBuffer), mHasHistoricalInfo(hasHistoricalInfo) {}
-
-    explicit LanguageModelDictContent(const bool hasHistoricalInfo)
-            : mTrieMap(), mHasHistoricalInfo(hasHistoricalInfo) {}
-
-    bool isNearSizeLimit() const {
-        return mTrieMap.isNearSizeLimit();
-    }
-
-    bool save(FILE *const file) const;
-
-    bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-            const LanguageModelDictContent *const originalContent,
-            int *const outNgramCount);
-
-    ProbabilityEntry getProbabilityEntry(const int wordId) const {
-        return getNgramProbabilityEntry(WordIdArrayView(), wordId);
-    }
-
-    bool setProbabilityEntry(const int wordId, const ProbabilityEntry *const probabilityEntry) {
-        return setNgramProbabilityEntry(WordIdArrayView(), wordId, probabilityEntry);
-    }
-
-    ProbabilityEntry getNgramProbabilityEntry(const WordIdArrayView prevWordIds,
-            const int wordId) const;
-
-    bool setNgramProbabilityEntry(const WordIdArrayView prevWordIds, const int wordId,
-            const ProbabilityEntry *const probabilityEntry);
-
- private:
-    DISALLOW_COPY_AND_ASSIGN(LanguageModelDictContent);
-
-    TrieMap mTrieMap;
-    const bool mHasHistoricalInfo;
-
-    bool runGCInner(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
-            const TrieMap::TrieMapRange trieMapRange, const int nextLevelBitmapEntryIndex,
-            int *const outNgramCount);
-
-    int getBitmapEntryIndex(const WordIdArrayView prevWordIds) const;
-};
-} // namespace latinime
-#endif /* LATINIME_LANGUAGE_MODEL_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
deleted file mode 100644
index 723808399..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+++ /dev/null
@@ -1,551 +0,0 @@
-/*
- * Copyright (C) 2013, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h"
-
-#include <vector>
-
-#include "suggest/core/dicnode/dic_node.h"
-#include "suggest/core/dicnode/dic_node_vector.h"
-#include "suggest/core/dictionary/ngram_listener.h"
-#include "suggest/core/dictionary/property/bigram_property.h"
-#include "suggest/core/dictionary/property/unigram_property.h"
-#include "suggest/core/dictionary/property/word_property.h"
-#include "suggest/core/session/prev_words_info.h"
-#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
-#include "suggest/policyimpl/dictionary/utils/probability_utils.h"
-
-namespace latinime {
-
-// Note that there are corresponding definitions in Java side in BinaryDictionaryTests and
-// BinaryDictionaryDecayingTests.
-const char *const Ver4PatriciaTriePolicy::UNIGRAM_COUNT_QUERY = "UNIGRAM_COUNT";
-const char *const Ver4PatriciaTriePolicy::BIGRAM_COUNT_QUERY = "BIGRAM_COUNT";
-const char *const Ver4PatriciaTriePolicy::MAX_UNIGRAM_COUNT_QUERY = "MAX_UNIGRAM_COUNT";
-const char *const Ver4PatriciaTriePolicy::MAX_BIGRAM_COUNT_QUERY = "MAX_BIGRAM_COUNT";
-const int Ver4PatriciaTriePolicy::MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS = 1024;
-const int Ver4PatriciaTriePolicy::MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS =
-        Ver4DictConstants::MAX_DICTIONARY_SIZE - MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
-
-void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNode,
-        DicNodeVector *const childDicNodes) const {
-    if (!dicNode->hasChildren()) {
-        return;
-    }
-    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
-    readingHelper.initWithPtNodeArrayPos(dicNode->getChildrenPtNodeArrayPos());
-    while (!readingHelper.isEnd()) {
-        const PtNodeParams ptNodeParams = readingHelper.getPtNodeParams();
-        if (!ptNodeParams.isValid()) {
-            break;
-        }
-        bool isTerminal = ptNodeParams.isTerminal() && !ptNodeParams.isDeleted();
-        if (isTerminal && mHeaderPolicy->isDecayingDict()) {
-            // A DecayingDict may have a terminal PtNode that has a terminal DicNode whose
-            // probability is NOT_A_PROBABILITY. In such case, we don't want to treat it as a
-            // valid terminal DicNode.
-            isTerminal = ptNodeParams.getProbability() != NOT_A_PROBABILITY;
-        }
-        readingHelper.readNextSiblingNode(ptNodeParams);
-        if (ptNodeParams.representsNonWordInfo()) {
-            // Skip PtNodes that represent non-word information.
-            continue;
-        }
-        childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getHeadPos(),
-                ptNodeParams.getChildrenPos(), ptNodeParams.getProbability(), isTerminal,
-                ptNodeParams.hasChildren(),
-                ptNodeParams.isBlacklisted()
-                        || ptNodeParams.isNotAWord() /* isBlacklistedOrNotAWord */,
-                ptNodeParams.getCodePointCount(), ptNodeParams.getCodePoints());
-    }
-    if (readingHelper.isError()) {
-        mIsCorrupted = true;
-        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
-    }
-}
-
-int Ver4PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
-        const int ptNodePos, const int maxCodePointCount, int *const outCodePoints,
-        int *const outUnigramProbability) const {
-    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
-    readingHelper.initWithPtNodePos(ptNodePos);
-    const int codePointCount =  readingHelper.getCodePointsAndProbabilityAndReturnCodePointCount(
-            maxCodePointCount, outCodePoints, outUnigramProbability);
-    if (readingHelper.isError()) {
-        mIsCorrupted = true;
-        AKLOGE("Dictionary reading error in getCodePointsAndProbabilityAndReturnCodePointCount().");
-    }
-    return codePointCount;
-}
-
-int Ver4PatriciaTriePolicy::getTerminalPtNodePositionOfWord(const int *const inWord,
-        const int length, const bool forceLowerCaseSearch) const {
-    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
-    readingHelper.initWithPtNodeArrayPos(getRootPosition());
-    const int ptNodePos =
-            readingHelper.getTerminalPtNodePositionOfWord(inWord, length, forceLowerCaseSearch);
-    if (readingHelper.isError()) {
-        mIsCorrupted = true;
-        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
-    }
-    return ptNodePos;
-}
-
-int Ver4PatriciaTriePolicy::getProbability(const int unigramProbability,
-        const int bigramProbability) const {
-    if (mHeaderPolicy->isDecayingDict()) {
-        // Both probabilities are encoded. Decode them and get probability.
-        return ForgettingCurveUtils::getProbability(unigramProbability, bigramProbability);
-    } else {
-        if (unigramProbability == NOT_A_PROBABILITY) {
-            return NOT_A_PROBABILITY;
-        } else if (bigramProbability == NOT_A_PROBABILITY) {
-            return ProbabilityUtils::backoff(unigramProbability);
-        } else {
-            return bigramProbability;
-        }
-    }
-}
-
-int Ver4PatriciaTriePolicy::getProbabilityOfPtNode(const int *const prevWordsPtNodePos,
-        const int ptNodePos) const {
-    if (ptNodePos == NOT_A_DICT_POS) {
-        return NOT_A_PROBABILITY;
-    }
-    const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
-    if (ptNodeParams.isDeleted() || ptNodeParams.isBlacklisted() || ptNodeParams.isNotAWord()) {
-        return NOT_A_PROBABILITY;
-    }
-    if (prevWordsPtNodePos) {
-        const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
-        BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
-        while (bigramsIt.hasNext()) {
-            bigramsIt.next();
-            if (bigramsIt.getBigramPos() == ptNodePos
-                    && bigramsIt.getProbability() != NOT_A_PROBABILITY) {
-                return getProbability(ptNodeParams.getProbability(), bigramsIt.getProbability());
-            }
-        }
-        return NOT_A_PROBABILITY;
-    }
-    return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
-}
-
-void Ver4PatriciaTriePolicy::iterateNgramEntries(const int *const prevWordsPtNodePos,
-        NgramListener *const listener) const {
-    if (!prevWordsPtNodePos) {
-        return;
-    }
-    const int bigramsPosition = getBigramsPositionOfPtNode(prevWordsPtNodePos[0]);
-    BinaryDictionaryBigramsIterator bigramsIt(&mBigramPolicy, bigramsPosition);
-    while (bigramsIt.hasNext()) {
-        bigramsIt.next();
-        listener->onVisitEntry(bigramsIt.getProbability(), bigramsIt.getBigramPos());
-    }
-}
-
-int Ver4PatriciaTriePolicy::getShortcutPositionOfPtNode(const int ptNodePos) const {
-    if (ptNodePos == NOT_A_DICT_POS) {
-        return NOT_A_DICT_POS;
-    }
-    const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
-    if (ptNodeParams.isDeleted()) {
-        return NOT_A_DICT_POS;
-    }
-    return mBuffers->getShortcutDictContent()->getShortcutListHeadPos(
-            ptNodeParams.getTerminalId());
-}
-
-int Ver4PatriciaTriePolicy::getBigramsPositionOfPtNode(const int ptNodePos) const {
-    if (ptNodePos == NOT_A_DICT_POS) {
-        return NOT_A_DICT_POS;
-    }
-    const PtNodeParams ptNodeParams(mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos));
-    if (ptNodeParams.isDeleted()) {
-        return NOT_A_DICT_POS;
-    }
-    return mBuffers->getBigramDictContent()->getBigramListHeadPos(
-            ptNodeParams.getTerminalId());
-}
-
-bool Ver4PatriciaTriePolicy::addUnigramEntry(const int *const word, const int length,
-        const UnigramProperty *const unigramProperty) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: addUnigramEntry() is called for non-updatable dictionary.");
-        return false;
-    }
-    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
-        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
-                mDictBuffer->getTailPosition());
-        return false;
-    }
-    if (length > MAX_WORD_LENGTH) {
-        AKLOGE("The word is too long to insert to the dictionary, length: %d", length);
-        return false;
-    }
-    for (const auto &shortcut : unigramProperty->getShortcuts()) {
-        if (shortcut.getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
-            AKLOGE("One of shortcut targets is too long to insert to the dictionary, length: %d",
-                    shortcut.getTargetCodePoints()->size());
-            return false;
-        }
-    }
-    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
-    readingHelper.initWithPtNodeArrayPos(getRootPosition());
-    bool addedNewUnigram = false;
-    int codePointsToAdd[MAX_WORD_LENGTH];
-    int codePointCountToAdd = length;
-    memmove(codePointsToAdd, word, sizeof(int) * length);
-    if (unigramProperty->representsBeginningOfSentence()) {
-        codePointCountToAdd = CharUtils::attachBeginningOfSentenceMarker(codePointsToAdd,
-                codePointCountToAdd, MAX_WORD_LENGTH);
-    }
-    if (codePointCountToAdd <= 0) {
-        return false;
-    }
-    if (mUpdatingHelper.addUnigramWord(&readingHelper, codePointsToAdd, codePointCountToAdd,
-            unigramProperty, &addedNewUnigram)) {
-        if (addedNewUnigram && !unigramProperty->representsBeginningOfSentence()) {
-            mUnigramCount++;
-        }
-        if (unigramProperty->getShortcuts().size() > 0) {
-            // Add shortcut target.
-            const int wordPos = getTerminalPtNodePositionOfWord(word, length,
-                    false /* forceLowerCaseSearch */);
-            if (wordPos == NOT_A_DICT_POS) {
-                AKLOGE("Cannot find terminal PtNode position to add shortcut target.");
-                return false;
-            }
-            for (const auto &shortcut : unigramProperty->getShortcuts()) {
-                if (!mUpdatingHelper.addShortcutTarget(wordPos,
-                        shortcut.getTargetCodePoints()->data(),
-                        shortcut.getTargetCodePoints()->size(), shortcut.getProbability())) {
-                    AKLOGE("Cannot add new shortcut target. PtNodePos: %d, length: %d, "
-                            "probability: %d", wordPos, shortcut.getTargetCodePoints()->size(),
-                            shortcut.getProbability());
-                    return false;
-                }
-            }
-        }
-        return true;
-    } else {
-        return false;
-    }
-}
-
-bool Ver4PatriciaTriePolicy::removeUnigramEntry(const int *const word, const int length) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: removeUnigramEntry() is called for non-updatable dictionary.");
-        return false;
-    }
-    const int ptNodePos = getTerminalPtNodePositionOfWord(word, length,
-            false /* forceLowerCaseSearch */);
-    if (ptNodePos == NOT_A_DICT_POS) {
-        return false;
-    }
-    const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-    if (!mNodeWriter.markPtNodeAsDeleted(&ptNodeParams)) {
-        AKLOGE("Cannot remove unigram. ptNodePos: %d", ptNodePos);
-        return false;
-    }
-    if (!ptNodeParams.representsNonWordInfo()) {
-        mUnigramCount--;
-    }
-    return true;
-}
-
-bool Ver4PatriciaTriePolicy::addNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const BigramProperty *const bigramProperty) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: addNgramEntry() is called for non-updatable dictionary.");
-        return false;
-    }
-    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
-        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
-                mDictBuffer->getTailPosition());
-        return false;
-    }
-    if (!prevWordsInfo->isValid()) {
-        AKLOGE("prev words info is not valid for adding n-gram entry to the dictionary.");
-        return false;
-    }
-    if (bigramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
-        AKLOGE("The word is too long to insert the ngram to the dictionary. "
-                "length: %d", bigramProperty->getTargetCodePoints()->size());
-        return false;
-    }
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
-            false /* tryLowerCaseSearch */);
-    const auto prevWordsPtNodePosView = PtNodePosArrayView::fromFixedSizeArray(prevWordsPtNodePos);
-    // TODO: Support N-gram.
-    if (prevWordsPtNodePos[0] == NOT_A_DICT_POS) {
-        if (prevWordsInfo->isNthPrevWordBeginningOfSentence(1 /* n */)) {
-            const std::vector<UnigramProperty::ShortcutProperty> shortcuts;
-            const UnigramProperty beginningOfSentenceUnigramProperty(
-                    true /* representsBeginningOfSentence */, true /* isNotAWord */,
-                    false /* isBlacklisted */, MAX_PROBABILITY /* probability */,
-                    NOT_A_TIMESTAMP /* timestamp */, 0 /* level */, 0 /* count */, &shortcuts);
-            if (!addUnigramEntry(prevWordsInfo->getNthPrevWordCodePoints(1 /* n */),
-                    prevWordsInfo->getNthPrevWordCodePointCount(1 /* n */),
-                    &beginningOfSentenceUnigramProperty)) {
-                AKLOGE("Cannot add unigram entry for the beginning-of-sentence.");
-                return false;
-            }
-            // Refresh Terminal PtNode positions.
-            prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
-                    false /* tryLowerCaseSearch */);
-        } else {
-            return false;
-        }
-    }
-    const int word1Pos = getTerminalPtNodePositionOfWord(
-            bigramProperty->getTargetCodePoints()->data(),
-            bigramProperty->getTargetCodePoints()->size(), false /* forceLowerCaseSearch */);
-    if (word1Pos == NOT_A_DICT_POS) {
-        return false;
-    }
-    bool addedNewEntry = false;
-    if (mUpdatingHelper.addNgramEntry(prevWordsPtNodePosView, word1Pos, bigramProperty,
-            &addedNewEntry)) {
-        if (addedNewEntry) {
-            mBigramCount++;
-        }
-        return true;
-    } else {
-        return false;
-    }
-}
-
-bool Ver4PatriciaTriePolicy::removeNgramEntry(const PrevWordsInfo *const prevWordsInfo,
-        const int *const word, const int length) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: removeNgramEntry() is called for non-updatable dictionary.");
-        return false;
-    }
-    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
-        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
-                mDictBuffer->getTailPosition());
-        return false;
-    }
-    if (!prevWordsInfo->isValid()) {
-        AKLOGE("prev words info is not valid for removing n-gram entry form the dictionary.");
-        return false;
-    }
-    if (length > MAX_WORD_LENGTH) {
-        AKLOGE("word is too long to remove n-gram entry form the dictionary. length: %d", length);
-    }
-    int prevWordsPtNodePos[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-    prevWordsInfo->getPrevWordsTerminalPtNodePos(this, prevWordsPtNodePos,
-            false /* tryLowerCaseSerch */);
-    const auto prevWordsPtNodePosView = PtNodePosArrayView::fromFixedSizeArray(prevWordsPtNodePos);
-    // TODO: Support N-gram.
-    if (prevWordsPtNodePos[0] == NOT_A_DICT_POS) {
-        return false;
-    }
-    const int wordPos = getTerminalPtNodePositionOfWord(word, length,
-            false /* forceLowerCaseSearch */);
-    if (wordPos == NOT_A_DICT_POS) {
-        return false;
-    }
-    if (mUpdatingHelper.removeNgramEntry(prevWordsPtNodePosView, wordPos)) {
-        mBigramCount--;
-        return true;
-    } else {
-        return false;
-    }
-}
-
-bool Ver4PatriciaTriePolicy::flush(const char *const filePath) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: flush() is called for non-updatable dictionary. filePath: %s", filePath);
-        return false;
-    }
-    if (!mWritingHelper.writeToDictFile(filePath, mUnigramCount, mBigramCount)) {
-        AKLOGE("Cannot flush the dictionary to file.");
-        mIsCorrupted = true;
-        return false;
-    }
-    return true;
-}
-
-bool Ver4PatriciaTriePolicy::flushWithGC(const char *const filePath) {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: flushWithGC() is called for non-updatable dictionary.");
-        return false;
-    }
-    if (!mWritingHelper.writeToDictFileWithGC(getRootPosition(), filePath)) {
-        AKLOGE("Cannot flush the dictionary to file with GC.");
-        mIsCorrupted = true;
-        return false;
-    }
-    return true;
-}
-
-bool Ver4PatriciaTriePolicy::needsToRunGC(const bool mindsBlockByGC) const {
-    if (!mBuffers->isUpdatable()) {
-        AKLOGI("Warning: needsToRunGC() is called for non-updatable dictionary.");
-        return false;
-    }
-    if (mBuffers->isNearSizeLimit()) {
-        // Additional buffer size is near the limit.
-        return true;
-    } else if (mHeaderPolicy->getExtendedRegionSize() + mDictBuffer->getUsedAdditionalBufferSize()
-            > Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE) {
-        // Total extended region size of the trie exceeds the limit.
-        return true;
-    } else if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS
-            && mDictBuffer->getUsedAdditionalBufferSize() > 0) {
-        // Needs to reduce dictionary size.
-        return true;
-    } else if (mHeaderPolicy->isDecayingDict()) {
-        return ForgettingCurveUtils::needsToDecay(mindsBlockByGC, mUnigramCount, mBigramCount,
-                mHeaderPolicy);
-    }
-    return false;
-}
-
-void Ver4PatriciaTriePolicy::getProperty(const char *const query, const int queryLength,
-        char *const outResult, const int maxResultLength) {
-    const int compareLength = queryLength + 1 /* terminator */;
-    if (strncmp(query, UNIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d", mUnigramCount);
-    } else if (strncmp(query, BIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d", mBigramCount);
-    } else if (strncmp(query, MAX_UNIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d",
-                mHeaderPolicy->isDecayingDict() ?
-                        ForgettingCurveUtils::getUnigramCountHardLimit(
-                                mHeaderPolicy->getMaxUnigramCount()) :
-                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
-    } else if (strncmp(query, MAX_BIGRAM_COUNT_QUERY, compareLength) == 0) {
-        snprintf(outResult, maxResultLength, "%d",
-                mHeaderPolicy->isDecayingDict() ?
-                        ForgettingCurveUtils::getBigramCountHardLimit(
-                                mHeaderPolicy->getMaxBigramCount()) :
-                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
-    }
-}
-
-const WordProperty Ver4PatriciaTriePolicy::getWordProperty(const int *const codePoints,
-        const int codePointCount) const {
-    const int ptNodePos = getTerminalPtNodePositionOfWord(codePoints, codePointCount,
-            false /* forceLowerCaseSearch */);
-    if (ptNodePos == NOT_A_DICT_POS) {
-        AKLOGE("getWordProperty is called for invalid word.");
-        return WordProperty();
-    }
-    const PtNodeParams ptNodeParams = mNodeReader.fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-    std::vector<int> codePointVector(ptNodeParams.getCodePoints(),
-            ptNodeParams.getCodePoints() + ptNodeParams.getCodePointCount());
-    const ProbabilityEntry probabilityEntry =
-            mBuffers->getLanguageModelDictContent()->getProbabilityEntry(
-                    ptNodeParams.getTerminalId());
-    const HistoricalInfo *const historicalInfo = probabilityEntry.getHistoricalInfo();
-    // Fetch bigram information.
-    std::vector<BigramProperty> bigrams;
-    const int bigramListPos = getBigramsPositionOfPtNode(ptNodePos);
-    if (bigramListPos != NOT_A_DICT_POS) {
-        int bigramWord1CodePoints[MAX_WORD_LENGTH];
-        const BigramDictContent *const bigramDictContent = mBuffers->getBigramDictContent();
-        const TerminalPositionLookupTable *const terminalPositionLookupTable =
-                mBuffers->getTerminalPositionLookupTable();
-        bool hasNext = true;
-        int readingPos = bigramListPos;
-        while (hasNext) {
-            const BigramEntry bigramEntry =
-                    bigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-            hasNext = bigramEntry.hasNext();
-            const int word1TerminalId = bigramEntry.getTargetTerminalId();
-            const int word1TerminalPtNodePos =
-                    terminalPositionLookupTable->getTerminalPtNodePosition(word1TerminalId);
-            if (word1TerminalPtNodePos == NOT_A_DICT_POS) {
-                continue;
-            }
-            // Word (unigram) probability
-            int word1Probability = NOT_A_PROBABILITY;
-            const int codePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
-                    word1TerminalPtNodePos, MAX_WORD_LENGTH, bigramWord1CodePoints,
-                    &word1Probability);
-            const std::vector<int> word1(bigramWord1CodePoints,
-                    bigramWord1CodePoints + codePointCount);
-            const HistoricalInfo *const historicalInfo = bigramEntry.getHistoricalInfo();
-            const int probability = bigramEntry.hasHistoricalInfo() ?
-                    ForgettingCurveUtils::decodeProbability(
-                            bigramEntry.getHistoricalInfo(), mHeaderPolicy) :
-                    bigramEntry.getProbability();
-            bigrams.emplace_back(&word1, probability,
-                    historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
-                    historicalInfo->getCount());
-        }
-    }
-    // Fetch shortcut information.
-    std::vector<UnigramProperty::ShortcutProperty> shortcuts;
-    int shortcutPos = getShortcutPositionOfPtNode(ptNodePos);
-    if (shortcutPos != NOT_A_DICT_POS) {
-        int shortcutTarget[MAX_WORD_LENGTH];
-        const ShortcutDictContent *const shortcutDictContent =
-                mBuffers->getShortcutDictContent();
-        bool hasNext = true;
-        while (hasNext) {
-            int shortcutTargetLength = 0;
-            int shortcutProbability = NOT_A_PROBABILITY;
-            shortcutDictContent->getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH, shortcutTarget,
-                    &shortcutTargetLength, &shortcutProbability, &hasNext, &shortcutPos);
-            const std::vector<int> target(shortcutTarget, shortcutTarget + shortcutTargetLength);
-            shortcuts.emplace_back(&target, shortcutProbability);
-        }
-    }
-    const UnigramProperty unigramProperty(ptNodeParams.representsBeginningOfSentence(),
-            ptNodeParams.isNotAWord(), ptNodeParams.isBlacklisted(), ptNodeParams.getProbability(),
-            historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
-            historicalInfo->getCount(), &shortcuts);
-    return WordProperty(&codePointVector, &unigramProperty, &bigrams);
-}
-
-int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outCodePoints,
-        int *const outCodePointCount) {
-    *outCodePointCount = 0;
-    if (token == 0) {
-        mTerminalPtNodePositionsForIteratingWords.clear();
-        DynamicPtReadingHelper::TraversePolicyToGetAllTerminalPtNodePositions traversePolicy(
-                &mTerminalPtNodePositionsForIteratingWords);
-        DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
-        readingHelper.initWithPtNodeArrayPos(getRootPosition());
-        readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(&traversePolicy);
-    }
-    const int terminalPtNodePositionsVectorSize =
-            static_cast<int>(mTerminalPtNodePositionsForIteratingWords.size());
-    if (token < 0 || token >= terminalPtNodePositionsVectorSize) {
-        AKLOGE("Given token %d is invalid.", token);
-        return 0;
-    }
-    const int terminalPtNodePos = mTerminalPtNodePositionsForIteratingWords[token];
-    int unigramProbability = NOT_A_PROBABILITY;
-    *outCodePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
-            terminalPtNodePos, MAX_WORD_LENGTH, outCodePoints, &unigramProbability);
-    const int nextToken = token + 1;
-    if (nextToken >= terminalPtNodePositionsVectorSize) {
-        // All words have been iterated.
-        mTerminalPtNodePositionsForIteratingWords.clear();
-        return 0;
-    }
-    return nextToken;
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
deleted file mode 100644
index 4220312e0..000000000
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
+++ /dev/null
@@ -1,294 +0,0 @@
-/*
- * Copyright (C) 2013, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h"
-
-#include <cstring>
-#include <queue>
-
-#include "suggest/policyimpl/dictionary/header/header_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h"
-#include "suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h"
-#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
-#include "suggest/policyimpl/dictionary/utils/file_utils.h"
-#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
-
-namespace latinime {
-
-bool Ver4PatriciaTrieWritingHelper::writeToDictFile(const char *const dictDirPath,
-        const int unigramCount, const int bigramCount) const {
-    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
-    BufferWithExtendableBuffer headerBuffer(
-            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
-    const int extendedRegionSize = headerPolicy->getExtendedRegionSize()
-            + mBuffers->getTrieBuffer()->getUsedAdditionalBufferSize();
-    if (!headerPolicy->fillInAndWriteHeaderToBuffer(false /* updatesLastDecayedTime */,
-            unigramCount, bigramCount, extendedRegionSize, &headerBuffer)) {
-        AKLOGE("Cannot write header structure to buffer. "
-                "updatesLastDecayedTime: %d, unigramCount: %d, bigramCount: %d, "
-                "extendedRegionSize: %d", false, unigramCount, bigramCount,
-                extendedRegionSize);
-        return false;
-    }
-    return mBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
-}
-
-bool Ver4PatriciaTrieWritingHelper::writeToDictFileWithGC(const int rootPtNodeArrayPos,
-        const char *const dictDirPath) {
-    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
-    Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers(
-            Ver4DictBuffers::createVer4DictBuffers(headerPolicy,
-                    Ver4DictConstants::MAX_DICTIONARY_SIZE));
-    int unigramCount = 0;
-    int bigramCount = 0;
-    if (!runGC(rootPtNodeArrayPos, headerPolicy, dictBuffers.get(), &unigramCount, &bigramCount)) {
-        return false;
-    }
-    BufferWithExtendableBuffer headerBuffer(
-            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
-    if (!headerPolicy->fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
-            unigramCount, bigramCount, 0 /* extendedRegionSize */, &headerBuffer)) {
-        return false;
-    }
-    return dictBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
-}
-
-bool Ver4PatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
-        const HeaderPolicy *const headerPolicy, Ver4DictBuffers *const buffersToWrite,
-        int *const outUnigramCount, int *const outBigramCount) {
-    Ver4PatriciaTrieNodeReader ptNodeReader(mBuffers->getTrieBuffer(),
-            mBuffers->getLanguageModelDictContent(), headerPolicy);
-    Ver4PtNodeArrayReader ptNodeArrayReader(mBuffers->getTrieBuffer());
-    Ver4BigramListPolicy bigramPolicy(mBuffers->getMutableBigramDictContent(),
-            mBuffers->getTerminalPositionLookupTable(), headerPolicy);
-    Ver4ShortcutListPolicy shortcutPolicy(mBuffers->getMutableShortcutDictContent(),
-            mBuffers->getTerminalPositionLookupTable());
-    Ver4PatriciaTrieNodeWriter ptNodeWriter(mBuffers->getWritableTrieBuffer(),
-            mBuffers, headerPolicy, &ptNodeReader, &ptNodeArrayReader, &bigramPolicy,
-            &shortcutPolicy);
-
-    DynamicPtReadingHelper readingHelper(&ptNodeReader, &ptNodeArrayReader);
-    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
-    DynamicPtGcEventListeners
-            ::TraversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
-                    traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted(
-                            &ptNodeWriter);
-    if (!readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
-            &traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted)) {
-        return false;
-    }
-    const int unigramCount = traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
-            .getValidUnigramCount();
-    const int maxUnigramCount = headerPolicy->getMaxUnigramCount();
-    if (headerPolicy->isDecayingDict() && unigramCount > maxUnigramCount) {
-        if (!truncateUnigrams(&ptNodeReader, &ptNodeWriter, maxUnigramCount)) {
-            AKLOGE("Cannot remove unigrams. current: %d, max: %d", unigramCount,
-                    maxUnigramCount);
-            return false;
-        }
-    }
-
-    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
-    DynamicPtGcEventListeners::TraversePolicyToUpdateBigramProbability
-            traversePolicyToUpdateBigramProbability(&ptNodeWriter);
-    if (!readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
-            &traversePolicyToUpdateBigramProbability)) {
-        return false;
-    }
-    const int bigramCount = traversePolicyToUpdateBigramProbability.getValidBigramEntryCount();
-    const int maxBigramCount = headerPolicy->getMaxBigramCount();
-    if (headerPolicy->isDecayingDict() && bigramCount > maxBigramCount) {
-        if (!truncateBigrams(maxBigramCount)) {
-            AKLOGE("Cannot remove bigrams. current: %d, max: %d", bigramCount, maxBigramCount);
-            return false;
-        }
-    }
-
-    // Mapping from positions in mBuffer to positions in bufferToWrite.
-    PtNodeWriter::DictPositionRelocationMap dictPositionRelocationMap;
-    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
-    Ver4PatriciaTrieNodeWriter ptNodeWriterForNewBuffers(buffersToWrite->getWritableTrieBuffer(),
-            buffersToWrite, headerPolicy, &ptNodeReader, &ptNodeArrayReader, &bigramPolicy,
-            &shortcutPolicy);
-    DynamicPtGcEventListeners::TraversePolicyToPlaceAndWriteValidPtNodesToBuffer
-            traversePolicyToPlaceAndWriteValidPtNodesToBuffer(&ptNodeWriterForNewBuffers,
-                    buffersToWrite->getWritableTrieBuffer(), &dictPositionRelocationMap);
-    if (!readingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
-            &traversePolicyToPlaceAndWriteValidPtNodesToBuffer)) {
-        return false;
-    }
-
-    // Create policy instances for the GCed dictionary.
-    Ver4PatriciaTrieNodeReader newPtNodeReader(buffersToWrite->getTrieBuffer(),
-            buffersToWrite->getLanguageModelDictContent(), headerPolicy);
-    Ver4PtNodeArrayReader newPtNodeArrayreader(buffersToWrite->getTrieBuffer());
-    Ver4BigramListPolicy newBigramPolicy(buffersToWrite->getMutableBigramDictContent(),
-            buffersToWrite->getTerminalPositionLookupTable(), headerPolicy);
-    Ver4ShortcutListPolicy newShortcutPolicy(buffersToWrite->getMutableShortcutDictContent(),
-            buffersToWrite->getTerminalPositionLookupTable());
-    Ver4PatriciaTrieNodeWriter newPtNodeWriter(buffersToWrite->getWritableTrieBuffer(),
-            buffersToWrite, headerPolicy, &newPtNodeReader, &newPtNodeArrayreader, &newBigramPolicy,
-            &newShortcutPolicy);
-    // Re-assign terminal IDs for valid terminal PtNodes.
-    TerminalPositionLookupTable::TerminalIdMap terminalIdMap;
-    if(!buffersToWrite->getMutableTerminalPositionLookupTable()->runGCTerminalIds(
-            &terminalIdMap)) {
-        return false;
-    }
-    // Run GC for probability dict content.
-    if (!buffersToWrite->getMutableLanguageModelDictContent()->runGC(&terminalIdMap,
-            mBuffers->getLanguageModelDictContent(), nullptr /* outNgramCount */)) {
-        return false;
-    }
-    // Run GC for bigram dict content.
-    if(!buffersToWrite->getMutableBigramDictContent()->runGC(&terminalIdMap,
-            mBuffers->getBigramDictContent(), outBigramCount)) {
-        return false;
-    }
-    // Run GC for shortcut dict content.
-    if(!buffersToWrite->getMutableShortcutDictContent()->runGC(&terminalIdMap,
-            mBuffers->getShortcutDictContent())) {
-        return false;
-    }
-    DynamicPtReadingHelper newDictReadingHelper(&newPtNodeReader, &newPtNodeArrayreader);
-    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
-    DynamicPtGcEventListeners::TraversePolicyToUpdateAllPositionFields
-            traversePolicyToUpdateAllPositionFields(&newPtNodeWriter, &dictPositionRelocationMap);
-    if (!newDictReadingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
-            &traversePolicyToUpdateAllPositionFields)) {
-        return false;
-    }
-    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
-    TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
-            traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds(&newPtNodeWriter, &terminalIdMap);
-    if (!newDictReadingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
-            &traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds)) {
-        return false;
-    }
-    *outUnigramCount = traversePolicyToUpdateAllPositionFields.getUnigramCount();
-    return true;
-}
-
-bool Ver4PatriciaTrieWritingHelper::truncateUnigrams(
-        const Ver4PatriciaTrieNodeReader *const ptNodeReader,
-        Ver4PatriciaTrieNodeWriter *const ptNodeWriter, const int maxUnigramCount) {
-    const TerminalPositionLookupTable *const terminalPosLookupTable =
-            mBuffers->getTerminalPositionLookupTable();
-    const int nextTerminalId = terminalPosLookupTable->getNextTerminalId();
-    std::priority_queue<DictProbability, std::vector<DictProbability>, DictProbabilityComparator>
-            priorityQueue;
-    for (int i = 0; i < nextTerminalId; ++i) {
-        const int terminalPos = terminalPosLookupTable->getTerminalPtNodePosition(i);
-        if (terminalPos == NOT_A_DICT_POS) {
-            continue;
-        }
-        const ProbabilityEntry probabilityEntry =
-                mBuffers->getLanguageModelDictContent()->getProbabilityEntry(i);
-        const int probability = probabilityEntry.hasHistoricalInfo() ?
-                ForgettingCurveUtils::decodeProbability(
-                        probabilityEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
-                probabilityEntry.getProbability();
-        priorityQueue.push(DictProbability(terminalPos, probability,
-                probabilityEntry.getHistoricalInfo()->getTimeStamp()));
-    }
-
-    // Delete unigrams.
-    while (static_cast<int>(priorityQueue.size()) > maxUnigramCount) {
-        const int ptNodePos = priorityQueue.top().getDictPos();
-        priorityQueue.pop();
-        const PtNodeParams ptNodeParams =
-                ptNodeReader->fetchPtNodeParamsInBufferFromPtNodePos(ptNodePos);
-        if (ptNodeParams.representsNonWordInfo()) {
-            continue;
-        }
-        if (!ptNodeWriter->markPtNodeAsWillBecomeNonTerminal(&ptNodeParams)) {
-            AKLOGE("Cannot mark PtNode as willBecomeNonterminal. PtNode pos: %d", ptNodePos);
-            return false;
-        }
-    }
-    return true;
-}
-
-bool Ver4PatriciaTrieWritingHelper::truncateBigrams(const int maxBigramCount) {
-    const TerminalPositionLookupTable *const terminalPosLookupTable =
-            mBuffers->getTerminalPositionLookupTable();
-    const int nextTerminalId = terminalPosLookupTable->getNextTerminalId();
-    std::priority_queue<DictProbability, std::vector<DictProbability>, DictProbabilityComparator>
-            priorityQueue;
-    BigramDictContent *const bigramDictContent = mBuffers->getMutableBigramDictContent();
-    for (int i = 0; i < nextTerminalId; ++i) {
-        const int bigramListPos = bigramDictContent->getBigramListHeadPos(i);
-        if (bigramListPos == NOT_A_DICT_POS) {
-            continue;
-        }
-        bool hasNext = true;
-        int readingPos = bigramListPos;
-        while (hasNext) {
-            const BigramEntry bigramEntry =
-                    bigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
-            const int entryPos = readingPos - bigramDictContent->getBigramEntrySize();
-            hasNext = bigramEntry.hasNext();
-            if (!bigramEntry.isValid()) {
-                continue;
-            }
-            const int probability = bigramEntry.hasHistoricalInfo() ?
-                    ForgettingCurveUtils::decodeProbability(
-                            bigramEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
-                    bigramEntry.getProbability();
-            priorityQueue.push(DictProbability(entryPos, probability,
-                    bigramEntry.getHistoricalInfo()->getTimeStamp()));
-        }
-    }
-
-    // Delete bigrams.
-    while (static_cast<int>(priorityQueue.size()) > maxBigramCount) {
-        const int entryPos = priorityQueue.top().getDictPos();
-        const BigramEntry bigramEntry = bigramDictContent->getBigramEntry(entryPos);
-        const BigramEntry invalidatedBigramEntry = bigramEntry.getInvalidatedEntry();
-        if (!bigramDictContent->writeBigramEntry(&invalidatedBigramEntry, entryPos)) {
-            AKLOGE("Cannot write bigram entry to remove. pos: %d", entryPos);
-            return false;
-        }
-        priorityQueue.pop();
-    }
-    return true;
-}
-
-bool Ver4PatriciaTrieWritingHelper::TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
-        ::onVisitingPtNode(const PtNodeParams *const ptNodeParams) {
-    if (!ptNodeParams->isTerminal()) {
-        return true;
-    }
-    TerminalPositionLookupTable::TerminalIdMap::const_iterator it =
-            mTerminalIdMap->find(ptNodeParams->getTerminalId());
-    if (it == mTerminalIdMap->end()) {
-        AKLOGE("terminal Id %d is not in the terminal position map. map size: %zd",
-                ptNodeParams->getTerminalId(), mTerminalIdMap->size());
-        return false;
-    }
-    if (!mPtNodeWriter->updateTerminalId(ptNodeParams, it->second)) {
-        AKLOGE("Cannot update terminal id. %d -> %d", it->first, it->second);
-        return false;
-    }
-    return true;
-}
-
-} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/typing/scoring_params.cpp b/native/jni/src/suggest/policyimpl/typing/scoring_params.cpp
index 3fc566e7a..856808a74 100644
--- a/native/jni/src/suggest/policyimpl/typing/scoring_params.cpp
+++ b/native/jni/src/suggest/policyimpl/typing/scoring_params.cpp
@@ -24,6 +24,7 @@ const int ScoringParams::THRESHOLD_NEXT_WORD_PROBABILITY_FOR_CAPPED = 120;
 const float ScoringParams::AUTOCORRECT_OUTPUT_THRESHOLD = 1.0f;
 
 const float ScoringParams::EXACT_MATCH_PROMOTION = 1.1f;
+const float ScoringParams::PERFECT_MATCH_PROMOTION = 1.1f;
 const float ScoringParams::CASE_ERROR_PENALTY_FOR_EXACT_MATCH = 0.01f;
 const float ScoringParams::ACCENT_ERROR_PENALTY_FOR_EXACT_MATCH = 0.02f;
 const float ScoringParams::DIGRAPH_PENALTY_FOR_EXACT_MATCH = 0.03f;
@@ -31,6 +32,7 @@ const float ScoringParams::DIGRAPH_PENALTY_FOR_EXACT_MATCH = 0.03f;
 // TODO: Unlimit max cache dic node size
 const int ScoringParams::MAX_CACHE_DIC_NODE_SIZE = 170;
 const int ScoringParams::MAX_CACHE_DIC_NODE_SIZE_FOR_SINGLE_POINT = 310;
+const int ScoringParams::MAX_CACHE_DIC_NODE_SIZE_FOR_LOW_PROBABILITY_LOCALE = 50;
 const int ScoringParams::THRESHOLD_SHORT_WORD_LENGTH = 4;
 
 const float ScoringParams::DISTANCE_WEIGHT_LENGTH = 0.1524f;
@@ -47,18 +49,21 @@ const float ScoringParams::INSERTION_COST_SAME_CHAR = 0.5508f;
 const float ScoringParams::INSERTION_COST_PROXIMITY_CHAR = 0.674f;
 const float ScoringParams::INSERTION_COST_FIRST_CHAR = 0.639f;
 const float ScoringParams::TRANSPOSITION_COST = 0.5608f;
-const float ScoringParams::SPACE_SUBSTITUTION_COST = 0.334f;
-const float ScoringParams::ADDITIONAL_PROXIMITY_COST = 0.4576f;
+const float ScoringParams::SPACE_SUBSTITUTION_COST = 0.33f;
+const float ScoringParams::SPACE_OMISSION_COST = 0.1f;
+const float ScoringParams::ADDITIONAL_PROXIMITY_COST = 0.37972f;
 const float ScoringParams::SUBSTITUTION_COST = 0.3806f;
-const float ScoringParams::COST_NEW_WORD = 0.0314f;
 const float ScoringParams::COST_SECOND_OR_LATER_WORD_FIRST_CHAR_UPPERCASE = 0.3224f;
 const float ScoringParams::DISTANCE_WEIGHT_LANGUAGE = 1.1214f;
 const float ScoringParams::COST_FIRST_COMPLETION = 0.4836f;
 const float ScoringParams::COST_COMPLETION = 0.00624f;
 const float ScoringParams::HAS_PROXIMITY_TERMINAL_COST = 0.0683f;
 const float ScoringParams::HAS_EDIT_CORRECTION_TERMINAL_COST = 0.0362f;
-const float ScoringParams::HAS_MULTI_WORD_TERMINAL_COST = 0.4182f;
+const float ScoringParams::HAS_MULTI_WORD_TERMINAL_COST = 0.3482f;
 const float ScoringParams::TYPING_BASE_OUTPUT_SCORE = 1.0f;
 const float ScoringParams::TYPING_MAX_OUTPUT_SCORE_PER_INPUT = 0.1f;
 const float ScoringParams::NORMALIZED_SPATIAL_DISTANCE_THRESHOLD_FOR_EDIT = 0.095f;
+const float ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_SUBSTITUTION = 0.99f;
+const float ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_OMISSION = 0.99f;
+const float ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SMALL_CACHE_SIZE = 0.99f;
 } // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/typing/scoring_params.h b/native/jni/src/suggest/policyimpl/typing/scoring_params.h
index b12de6d87..6f327a370 100644
--- a/native/jni/src/suggest/policyimpl/typing/scoring_params.h
+++ b/native/jni/src/suggest/policyimpl/typing/scoring_params.h
@@ -30,9 +30,11 @@ class ScoringParams {
     static const float AUTOCORRECT_OUTPUT_THRESHOLD;
     static const int MAX_CACHE_DIC_NODE_SIZE;
     static const int MAX_CACHE_DIC_NODE_SIZE_FOR_SINGLE_POINT;
+    static const int MAX_CACHE_DIC_NODE_SIZE_FOR_LOW_PROBABILITY_LOCALE;
     static const int THRESHOLD_SHORT_WORD_LENGTH;
 
     static const float EXACT_MATCH_PROMOTION;
+    static const float PERFECT_MATCH_PROMOTION;
     static const float CASE_ERROR_PENALTY_FOR_EXACT_MATCH;
     static const float ACCENT_ERROR_PENALTY_FOR_EXACT_MATCH;
     static const float DIGRAPH_PENALTY_FOR_EXACT_MATCH;
@@ -55,9 +57,9 @@ class ScoringParams {
     static const float INSERTION_COST_FIRST_CHAR;
     static const float TRANSPOSITION_COST;
     static const float SPACE_SUBSTITUTION_COST;
+    static const float SPACE_OMISSION_COST;
     static const float ADDITIONAL_PROXIMITY_COST;
     static const float SUBSTITUTION_COST;
-    static const float COST_NEW_WORD;
     static const float COST_SECOND_OR_LATER_WORD_FIRST_CHAR_UPPERCASE;
     static const float DISTANCE_WEIGHT_LANGUAGE;
     static const float COST_FIRST_COMPLETION;
@@ -68,6 +70,9 @@ class ScoringParams {
     static const float TYPING_BASE_OUTPUT_SCORE;
     static const float TYPING_MAX_OUTPUT_SCORE_PER_INPUT;
     static const float NORMALIZED_SPATIAL_DISTANCE_THRESHOLD_FOR_EDIT;
+    static const float LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_SUBSTITUTION;
+    static const float LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_OMISSION;
+    static const float LOCALE_WEIGHT_THRESHOLD_FOR_SMALL_CACHE_SIZE;
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(ScoringParams);
diff --git a/native/jni/src/suggest/policyimpl/typing/typing_scoring.h b/native/jni/src/suggest/policyimpl/typing/typing_scoring.h
index 04cb6603a..6acd767ea 100644
--- a/native/jni/src/suggest/policyimpl/typing/typing_scoring.h
+++ b/native/jni/src/suggest/policyimpl/typing/typing_scoring.h
@@ -33,32 +33,61 @@ class TypingScoring : public Scoring {
     static const TypingScoring *getInstance() { return &sInstance; }
 
     AK_FORCE_INLINE void getMostProbableString(const DicTraverseSession *const traverseSession,
-            const float languageWeight, SuggestionResults *const outSuggestionResults) const {}
+            const float weightOfLangModelVsSpatialModel,
+            SuggestionResults *const outSuggestionResults) const {}
 
-    AK_FORCE_INLINE float getAdjustedLanguageWeight(DicTraverseSession *const traverseSession,
-            DicNode *const terminals, const int size) const {
+    AK_FORCE_INLINE float getAdjustedWeightOfLangModelVsSpatialModel(
+            DicTraverseSession *const traverseSession, DicNode *const terminals,
+            const int size) const {
         return 1.0f;
     }
 
     AK_FORCE_INLINE int calculateFinalScore(const float compoundDistance, const int inputSize,
             const ErrorTypeUtils::ErrorType containedErrorTypes, const bool forceCommit,
-            const bool boostExactMatches) const {
+            const bool boostExactMatches, const bool hasProbabilityZero) const {
         const float maxDistance = ScoringParams::DISTANCE_WEIGHT_LANGUAGE
                 + static_cast<float>(inputSize) * ScoringParams::TYPING_MAX_OUTPUT_SCORE_PER_INPUT;
         float score = ScoringParams::TYPING_BASE_OUTPUT_SCORE - compoundDistance / maxDistance;
         if (forceCommit) {
             score += ScoringParams::AUTOCORRECT_OUTPUT_THRESHOLD;
         }
-        if (boostExactMatches && ErrorTypeUtils::isExactMatch(containedErrorTypes)) {
-            score += ScoringParams::EXACT_MATCH_PROMOTION;
-            if ((ErrorTypeUtils::MATCH_WITH_CASE_ERROR & containedErrorTypes) != 0) {
-                score -= ScoringParams::CASE_ERROR_PENALTY_FOR_EXACT_MATCH;
+        if (hasProbabilityZero) {
+            // Previously, when both legitimate 0-frequency words (such as distracters) and
+            // offensive words were encoded in the same way, distracters would never show up
+            // when the user blocked offensive words (the default setting, as well as the
+            // setting for regression tests).
+            //
+            // When b/11031090 was fixed and a separate encoding was used for offensive words,
+            // 0-frequency words would no longer be blocked when they were an "exact match"
+            // (where case mismatches and accent mismatches would be considered an "exact
+            // match"). The exact match boosting functionality meant that, for example, when
+            // the user typed "mt" they would be suggested the word "Mt", although they most
+            // probably meant to type "my".
+            //
+            // For this reason, we introduced this change, which does the following:
+            // * Defines the "perfect match" as a really exact match, with no room for case or
+            // accent mismatches
+            // * When the target word has probability zero (as "Mt" does, because it is a
+            // distracter), ONLY boost its score if it is a perfect match.
+            //
+            // By doing this, when the user types "mt", the word "Mt" will NOT be boosted, and
+            // they will get "my". However, if the user makes an explicit effort to type "Mt",
+            // we do boost the word "Mt" so that the user's input is not autocorrected to "My".
+            if (boostExactMatches && ErrorTypeUtils::isPerfectMatch(containedErrorTypes)) {
+                score += ScoringParams::PERFECT_MATCH_PROMOTION;
             }
-            if ((ErrorTypeUtils::MATCH_WITH_ACCENT_ERROR & containedErrorTypes) != 0) {
-                score -= ScoringParams::ACCENT_ERROR_PENALTY_FOR_EXACT_MATCH;
-            }
-            if ((ErrorTypeUtils::MATCH_WITH_DIGRAPH & containedErrorTypes) != 0) {
-                score -= ScoringParams::DIGRAPH_PENALTY_FOR_EXACT_MATCH;
+        } else {
+            if (boostExactMatches && ErrorTypeUtils::isExactMatch(containedErrorTypes)) {
+                score += ScoringParams::EXACT_MATCH_PROMOTION;
+                if ((ErrorTypeUtils::MATCH_WITH_WRONG_CASE & containedErrorTypes) != 0) {
+                    score -= ScoringParams::CASE_ERROR_PENALTY_FOR_EXACT_MATCH;
+                }
+                if ((ErrorTypeUtils::MATCH_WITH_MISSING_ACCENT & containedErrorTypes) != 0) {
+                    score -= ScoringParams::ACCENT_ERROR_PENALTY_FOR_EXACT_MATCH;
+                }
+                if ((ErrorTypeUtils::MATCH_WITH_DIGRAPH & containedErrorTypes) != 0) {
+                    score -= ScoringParams::DIGRAPH_PENALTY_FOR_EXACT_MATCH;
+                }
             }
         }
         return static_cast<int>(score * SUGGEST_INTERFACE_OUTPUT_SCALE);
diff --git a/native/jni/src/suggest/policyimpl/typing/typing_traversal.h b/native/jni/src/suggest/policyimpl/typing/typing_traversal.h
index cb3dfac70..b9b6314ae 100644
--- a/native/jni/src/suggest/policyimpl/typing/typing_traversal.h
+++ b/native/jni/src/suggest/policyimpl/typing/typing_traversal.h
@@ -26,6 +26,7 @@
 #include "suggest/core/layout/proximity_info_utils.h"
 #include "suggest/core/policy/traversal.h"
 #include "suggest/core/session/dic_traverse_session.h"
+#include "suggest/core/suggest_options.h"
 #include "suggest/policyimpl/typing/scoring_params.h"
 #include "utils/char_utils.h"
 
@@ -77,6 +78,13 @@ class TypingTraversal : public Traversal {
         if (!CORRECT_NEW_WORD_SPACE_SUBSTITUTION) {
             return false;
         }
+        if (traverseSession->getSuggestOptions()->weightForLocale()
+                < ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_SUBSTITUTION) {
+            // Space substitution is heavy, so we skip doing it if the weight for this language
+            // is low because we anticipate the suggestions out of this dictionary are not for
+            // the language the user intends to type in.
+            return false;
+        }
         if (!canDoLookAheadCorrection(traverseSession, dicNode)) {
             return false;
         }
@@ -91,6 +99,13 @@ class TypingTraversal : public Traversal {
         if (!CORRECT_NEW_WORD_SPACE_OMISSION) {
             return false;
         }
+        if (traverseSession->getSuggestOptions()->weightForLocale()
+                < ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SPACE_OMISSION) {
+            // Space omission is heavy, so we skip doing it if the weight for this language
+            // is low because we anticipate the suggestions out of this dictionary are not for
+            // the language the user intends to type in.
+            return false;
+        }
         const int inputSize = traverseSession->getInputSize();
         // TODO: Don't refer to isCompletion?
         if (dicNode->isCompletion(inputSize)) {
@@ -141,9 +156,14 @@ class TypingTraversal : public Traversal {
         return DicNodeVector::DEFAULT_NODES_SIZE_FOR_OPTIMIZATION;
     }
 
-    AK_FORCE_INLINE int getMaxCacheSize(const int inputSize) const {
-        return (inputSize <= 1) ? ScoringParams::MAX_CACHE_DIC_NODE_SIZE_FOR_SINGLE_POINT
-                : ScoringParams::MAX_CACHE_DIC_NODE_SIZE;
+    AK_FORCE_INLINE int getMaxCacheSize(const int inputSize, const float weightForLocale) const {
+        if (inputSize <= 1) {
+            return ScoringParams::MAX_CACHE_DIC_NODE_SIZE_FOR_SINGLE_POINT;
+        }
+        if (weightForLocale < ScoringParams::LOCALE_WEIGHT_THRESHOLD_FOR_SMALL_CACHE_SIZE) {
+            return ScoringParams::MAX_CACHE_DIC_NODE_SIZE_FOR_LOW_PROBABILITY_LOCALE;
+        }
+        return ScoringParams::MAX_CACHE_DIC_NODE_SIZE;
     }
 
     AK_FORCE_INLINE int getTerminalCacheSize() const {
@@ -161,8 +181,8 @@ class TypingTraversal : public Traversal {
         return true;
     }
 
-    AK_FORCE_INLINE bool isGoodToTraverseNextWord(const DicNode *const dicNode) const {
-        const int probability = dicNode->getProbability();
+    AK_FORCE_INLINE bool isGoodToTraverseNextWord(const DicNode *const dicNode,
+            const int probability) const {
         if (probability < ScoringParams::THRESHOLD_NEXT_WORD_PROBABILITY) {
             return false;
         }
diff --git a/native/jni/src/suggest/policyimpl/typing/typing_weighting.cpp b/native/jni/src/suggest/policyimpl/typing/typing_weighting.cpp
index 54f65c786..a0e54115d 100644
--- a/native/jni/src/suggest/policyimpl/typing/typing_weighting.cpp
+++ b/native/jni/src/suggest/policyimpl/typing/typing_weighting.cpp
@@ -17,6 +17,7 @@
 #include "suggest/policyimpl/typing/typing_weighting.h"
 
 #include "suggest/core/dicnode/dic_node.h"
+#include "suggest/core/layout/proximity_info.h"
 #include "suggest/policyimpl/typing/scoring_params.h"
 
 namespace latinime {
@@ -36,30 +37,49 @@ ErrorTypeUtils::ErrorType TypingWeighting::getErrorType(const CorrectionType cor
                 // Compare the node code point with original primary code point on the keyboard.
                 const ProximityInfoState *const pInfoState =
                         traverseSession->getProximityInfoState(0);
-                const int primaryOriginalCodePoint = pInfoState->getPrimaryOriginalCodePointAt(
+                const int primaryCodePoint = pInfoState->getPrimaryCodePointAt(
                         dicNode->getInputIndex(0));
                 const int nodeCodePoint = dicNode->getNodeCodePoint();
-                if (primaryOriginalCodePoint == nodeCodePoint) {
+                const int keyIndex = traverseSession->getProximityInfo()->getKeyIndexOf(
+                        primaryCodePoint);
+                // TODO: Check whether the input code point is on the keyboard.
+                if (primaryCodePoint == nodeCodePoint) {
                     // Node code point is same as original code point on the keyboard.
                     return ErrorTypeUtils::NOT_AN_ERROR;
-                } else if (CharUtils::toLowerCase(primaryOriginalCodePoint) ==
+                } else if (CharUtils::toLowerCase(primaryCodePoint) ==
                         CharUtils::toLowerCase(nodeCodePoint)) {
                     // Only cases of the code points are different.
-                    return ErrorTypeUtils::MATCH_WITH_CASE_ERROR;
-                } else if (CharUtils::toBaseCodePoint(primaryOriginalCodePoint) ==
-                        CharUtils::toBaseCodePoint(nodeCodePoint)) {
+                    return ErrorTypeUtils::MATCH_WITH_WRONG_CASE;
+                } else if (primaryCodePoint == CharUtils::toBaseCodePoint(nodeCodePoint)) {
                     // Node code point is a variant of original code point.
-                    return ErrorTypeUtils::MATCH_WITH_ACCENT_ERROR;
-                } else {
+                    return ErrorTypeUtils::MATCH_WITH_MISSING_ACCENT;
+                } else if (CharUtils::toBaseCodePoint(primaryCodePoint)
+                        == CharUtils::toBaseCodePoint(nodeCodePoint)) {
+                    // Base code points are the same but the code point is intentionally input.
+                    if (keyIndex == NOT_AN_INDEX) {
+                        return ErrorTypeUtils::MATCH_WITH_MISSING_EXPLICIT_ACCENT;
+                    }
+                    return ErrorTypeUtils::MATCH_WITH_WRONG_ACCENT;
+                } else if (CharUtils::toLowerCase(primaryCodePoint)
+                        == CharUtils::toBaseLowerCase(nodeCodePoint)) {
                     // Node code point is a variant of original code point and the cases are also
                     // different.
-                    return ErrorTypeUtils::MATCH_WITH_ACCENT_ERROR
-                            | ErrorTypeUtils::MATCH_WITH_CASE_ERROR;
+                    return ErrorTypeUtils::MATCH_WITH_MISSING_ACCENT
+                            | ErrorTypeUtils::MATCH_WITH_WRONG_CASE;
+                } else {
+                    if (keyIndex == NOT_AN_INDEX) {
+                        return ErrorTypeUtils::MATCH_WITH_MISSING_EXPLICIT_ACCENT
+                                | ErrorTypeUtils::MATCH_WITH_WRONG_CASE;
+                    }
+                    // Base code points are the same and the cases are different.
+                    return ErrorTypeUtils::MATCH_WITH_WRONG_ACCENT
+                            | ErrorTypeUtils::MATCH_WITH_WRONG_CASE;
                 }
             }
             break;
         case CT_ADDITIONAL_PROXIMITY:
-            return  ErrorTypeUtils::PROXIMITY_CORRECTION;
+            // TODO: Change to EDIT_CORRECTION.
+            return ErrorTypeUtils::PROXIMITY_CORRECTION;
         case CT_OMISSION:
             if (parentDicNode->canBeIntentionalOmission()) {
                 return ErrorTypeUtils::INTENTIONAL_OMISSION;
@@ -68,6 +88,8 @@ ErrorTypeUtils::ErrorType TypingWeighting::getErrorType(const CorrectionType cor
             }
             break;
         case CT_SUBSTITUTION:
+            // TODO: Quit settng PROXIMITY_CORRECTION.
+            return ErrorTypeUtils::EDIT_CORRECTION | ErrorTypeUtils::PROXIMITY_CORRECTION;
         case CT_INSERTION:
         case CT_TERMINAL_INSERTION:
         case CT_TRANSPOSITION:
diff --git a/native/jni/src/suggest/policyimpl/typing/typing_weighting.h b/native/jni/src/suggest/policyimpl/typing/typing_weighting.h
index 84077174d..1338ac81a 100644
--- a/native/jni/src/suggest/policyimpl/typing/typing_weighting.h
+++ b/native/jni/src/suggest/policyimpl/typing/typing_weighting.h
@@ -150,9 +150,10 @@ class TypingWeighting : public Weighting {
         return cost + weightedDistance;
     }
 
-    float getNewWordSpatialCost(const DicTraverseSession *const traverseSession,
+    float getSpaceOmissionCost(const DicTraverseSession *const traverseSession,
             const DicNode *const dicNode, DicNode_InputStateG *inputStateG) const {
-        return ScoringParams::COST_NEW_WORD * traverseSession->getMultiWordCostMultiplier();
+        const float cost = ScoringParams::SPACE_OMISSION_COST;
+        return cost * traverseSession->getMultiWordCostMultiplier();
     }
 
     float getNewWordBigramLanguageCost(const DicTraverseSession *const traverseSession,
@@ -202,7 +203,10 @@ class TypingWeighting : public Weighting {
 
     AK_FORCE_INLINE float getSpaceSubstitutionCost(const DicTraverseSession *const traverseSession,
             const DicNode *const dicNode) const {
-        const float cost = ScoringParams::SPACE_SUBSTITUTION_COST + ScoringParams::COST_NEW_WORD;
+        const int inputIndex = dicNode->getInputIndex(0);
+        const float distanceToSpaceKey = traverseSession->getProximityInfoState(0)
+                ->getPointToKeyLength(inputIndex, KEYCODE_SPACE);
+        const float cost = ScoringParams::SPACE_SUBSTITUTION_COST * distanceToSpaceKey;
         return cost * traverseSession->getMultiWordCostMultiplier();
     }
 
diff --git a/native/jni/src/utils/byte_array_view.h b/native/jni/src/utils/byte_array_view.h
index 2c97c6d58..2b778af6f 100644
--- a/native/jni/src/utils/byte_array_view.h
+++ b/native/jni/src/utils/byte_array_view.h
@@ -42,6 +42,13 @@ class ReadOnlyByteArrayView {
         return mPtr;
     }
 
+    AK_FORCE_INLINE const ReadOnlyByteArrayView skip(const size_t n) const {
+        if (mSize <= n) {
+            return ReadOnlyByteArrayView();
+        }
+        return ReadOnlyByteArrayView(mPtr + n, mSize - n);
+    }
+
  private:
     DISALLOW_ASSIGNMENT_OPERATOR(ReadOnlyByteArrayView);
 
@@ -77,10 +84,12 @@ class ReadWriteByteArrayView {
     }
 
  private:
-    DISALLOW_ASSIGNMENT_OPERATOR(ReadWriteByteArrayView);
+    // Default copy constructor and assignment operator are used for using this class with STL
+    // containers.
 
-    uint8_t *const mPtr;
-    const size_t mSize;
+    // These members cannot be const to have the assignment operator.
+    uint8_t *mPtr;
+    size_t mSize;
 };
 
 } // namespace latinime
diff --git a/native/jni/src/utils/char_utils.cpp b/native/jni/src/utils/char_utils.cpp
index b17e0847d..a43e6dd62 100644
--- a/native/jni/src/utils/char_utils.cpp
+++ b/native/jni/src/utils/char_utils.cpp
@@ -1057,11 +1057,11 @@ static int compare_pair_capital(const void *a, const void *b) {
             - static_cast<int>((static_cast<const struct LatinCapitalSmallPair *>(b))->capital);
 }
 
-/* static */ unsigned short CharUtils::latin_tolower(const unsigned short c) {
+/* static */ int CharUtils::latin_tolower(const int c) {
     struct LatinCapitalSmallPair *p =
             static_cast<struct LatinCapitalSmallPair *>(bsearch(&c, SORTED_CHAR_MAP,
                     NELEMS(SORTED_CHAR_MAP), sizeof(SORTED_CHAR_MAP[0]), compare_pair_capital));
-    return p ? p->small : c;
+    return p ? static_cast<int>(p->small) : c;
 }
 
 /*
@@ -1117,7 +1117,9 @@ static int compare_pair_capital(const void *a, const void *b) {
           // TODO: Check if it's really acceptable to consider ø a diacritical variant of o
     /* U+0100 */ 0x0041, 0x0061, 0x0041, 0x0061, 0x0041, 0x0061, 0x0043, 0x0063,
     /* U+0108 */ 0x0043, 0x0063, 0x0043, 0x0063, 0x0043, 0x0063, 0x0044, 0x0064,
-    /* U+0110 */ 0x0110, 0x0111, 0x0045, 0x0065, 0x0045, 0x0065, 0x0045, 0x0065,
+    /* U+0110 */ 0x0046, 0x0064, 0x0045, 0x0065, 0x0045, 0x0065, 0x0045, 0x0065,
+        // U+0110: Manually changed from 0110 to 0046
+        // U+0111: Manually changed from 0111 to 0064
     /* U+0118 */ 0x0045, 0x0065, 0x0045, 0x0065, 0x0047, 0x0067, 0x0047, 0x0067,
     /* U+0120 */ 0x0047, 0x0067, 0x0047, 0x0067, 0x0048, 0x0068, 0x0126, 0x0127,
     /* U+0128 */ 0x0049, 0x0069, 0x0049, 0x0069, 0x0049, 0x0069, 0x0049, 0x0069,
@@ -1135,6 +1137,9 @@ static int compare_pair_capital(const void *a, const void *b) {
     /* U+0170 */ 0x0055, 0x0075, 0x0055, 0x0075, 0x0057, 0x0077, 0x0059, 0x0079,
     /* U+0178 */ 0x0059, 0x005A, 0x007A, 0x005A, 0x007A, 0x005A, 0x007A, 0x0073,
     /* U+0180 */ 0x0180, 0x0181, 0x0182, 0x0183, 0x0184, 0x0185, 0x0186, 0x0187,
+          // TODO: A lot of letters are their own base code points, but for
+          // some (e.g. U+0180) it doesn't seem right. Ideally each code point should
+          // be checked individually with all languages it's used in.
     /* U+0188 */ 0x0188, 0x0189, 0x018A, 0x018B, 0x018C, 0x018D, 0x018E, 0x018F,
     /* U+0190 */ 0x0190, 0x0191, 0x0192, 0x0193, 0x0194, 0x0195, 0x0196, 0x0197,
     /* U+0198 */ 0x0198, 0x0199, 0x019A, 0x019B, 0x019C, 0x019D, 0x019E, 0x019F,
diff --git a/native/jni/src/utils/char_utils.h b/native/jni/src/utils/char_utils.h
index 63786502b..7871c26ef 100644
--- a/native/jni/src/utils/char_utils.h
+++ b/native/jni/src/utils/char_utils.h
@@ -27,20 +27,14 @@ namespace latinime {
 
 class CharUtils {
  public:
+    static const std::vector<int> EMPTY_STRING;
+
     static AK_FORCE_INLINE bool isAsciiUpper(int c) {
         // Note: isupper(...) reports false positives for some Cyrillic characters, causing them to
         // be incorrectly lower-cased using toAsciiLower(...) rather than latin_tolower(...).
         return (c >= 'A' && c <= 'Z');
     }
 
-    static AK_FORCE_INLINE int toAsciiLower(int c) {
-        return c - 'A' + 'a';
-    }
-
-    static AK_FORCE_INLINE bool isAscii(int c) {
-        return isascii(c) != 0;
-    }
-
     static AK_FORCE_INLINE int toLowerCase(const int c) {
         if (isAsciiUpper(c)) {
             return toAsciiLower(c);
@@ -48,7 +42,7 @@ class CharUtils {
         if (isAscii(c)) {
             return c;
         }
-        return static_cast<int>(latin_tolower(static_cast<unsigned short>(c)));
+        return latin_tolower(c);
     }
 
     static AK_FORCE_INLINE int toBaseLowerCase(const int c) {
@@ -59,7 +53,6 @@ class CharUtils {
         // TODO: Do not hardcode here
         return codePoint == KEYCODE_SINGLE_QUOTE || codePoint == KEYCODE_HYPHEN_MINUS;
     }
-
     static AK_FORCE_INLINE int getCodePointCount(const int arraySize, const int *const codePoints) {
         int size = 0;
         for (; size < arraySize; ++size) {
@@ -91,9 +84,6 @@ class CharUtils {
         return codePoint >= MIN_UNICODE_CODE_POINT && codePoint <= MAX_UNICODE_CODE_POINT;
     }
 
-    static unsigned short latin_tolower(const unsigned short c);
-    static const std::vector<int> EMPTY_STRING;
-
     // Returns updated code point count. Returns 0 when the code points cannot be marked as a
     // Beginning-of-Sentence.
     static AK_FORCE_INLINE int attachBeginningOfSentenceMarker(int *const codePoints,
@@ -111,6 +101,17 @@ class CharUtils {
         return codePointCount + 1;
     }
 
+    // Returns updated code point count.
+    static AK_FORCE_INLINE int removeBeginningOfSentenceMarker(int *const codePoints,
+            const int codePointCount) {
+        if (codePointCount <= 0 || codePoints[0] != CODE_POINT_BEGINNING_OF_SENTENCE) {
+            return codePointCount;
+        }
+        const int newCodePointCount = codePointCount - 1;
+        memmove(codePoints, codePoints + 1, sizeof(int) * newCodePointCount);
+        return newCodePointCount;
+    }
+
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(CharUtils);
 
@@ -125,6 +126,16 @@ class CharUtils {
      */
     static const int BASE_CHARS_SIZE = 0x0500;
     static const unsigned short BASE_CHARS[BASE_CHARS_SIZE];
+
+    static AK_FORCE_INLINE bool isAscii(int c) {
+        return isascii(c) != 0;
+    }
+
+    static AK_FORCE_INLINE int toAsciiLower(int c) {
+        return c - 'A' + 'a';
+    }
+
+    static int latin_tolower(const int c);
 };
 } // namespace latinime
 #endif // LATINIME_CHAR_UTILS_H
diff --git a/native/jni/src/utils/int_array_view.h b/native/jni/src/utils/int_array_view.h
index c1ddc9812..e0f671056 100644
--- a/native/jni/src/utils/int_array_view.h
+++ b/native/jni/src/utils/int_array_view.h
@@ -17,8 +17,10 @@
 #ifndef LATINIME_INT_ARRAY_VIEW_H
 #define LATINIME_INT_ARRAY_VIEW_H
 
+#include <algorithm>
+#include <array>
 #include <cstdint>
-#include <cstdlib>
+#include <cstring>
 #include <vector>
 
 #include "defines.h"
@@ -56,14 +58,14 @@ class IntArrayView {
     explicit IntArrayView(const std::vector<int> &vector)
             : mPtr(vector.data()), mSize(vector.size()) {}
 
-    template <int N>
-    AK_FORCE_INLINE static IntArrayView fromFixedSizeArray(const int (&array)[N]) {
-        return IntArrayView(array, N);
+    template <size_t N>
+    AK_FORCE_INLINE static IntArrayView fromArray(const std::array<int, N> &array) {
+        return IntArrayView(array.data(), array.size());
     }
 
-    // Returns a view that points one int object. Does not take ownership of the given object.
-    AK_FORCE_INLINE static IntArrayView fromObject(const int *const object) {
-        return IntArrayView(object, 1);
+    // Returns a view that points one int object.
+    AK_FORCE_INLINE static IntArrayView singleElementView(const int *const ptr) {
+        return IntArrayView(ptr, 1);
     }
 
     AK_FORCE_INLINE int operator[](const size_t index) const {
@@ -91,6 +93,69 @@ class IntArrayView {
         return mPtr + mSize;
     }
 
+    AK_FORCE_INLINE bool contains(const int value) const {
+        return std::find(begin(), end(), value) != end();
+    }
+
+    // Returns the view whose size is smaller than or equal to the given count.
+    AK_FORCE_INLINE const IntArrayView limit(const size_t maxSize) const {
+        return IntArrayView(mPtr, std::min(maxSize, mSize));
+    }
+
+    AK_FORCE_INLINE const IntArrayView skip(const size_t n) const {
+        if (mSize <= n) {
+            return IntArrayView();
+        }
+        return IntArrayView(mPtr + n, mSize - n);
+    }
+
+    template <size_t N>
+    void copyToArray(std::array<int, N> *const buffer, const size_t offset) const {
+        ASSERT(mSize + offset <= N);
+        memmove(buffer->data() + offset, mPtr, sizeof(int) * mSize);
+    }
+
+    AK_FORCE_INLINE int firstOrDefault(const int defaultValue) const {
+        if (empty()) {
+            return defaultValue;
+        }
+        return mPtr[0];
+    }
+
+    AK_FORCE_INLINE int lastOrDefault(const int defaultValue) const {
+        if (empty()) {
+            return defaultValue;
+        }
+        return mPtr[mSize - 1];
+    }
+
+    AK_FORCE_INLINE std::vector<int> toVector() const {
+        return std::vector<int>(begin(), end());
+    }
+
+    std::vector<IntArrayView> split(const int separator, const int limit = S_INT_MAX) const {
+        if (limit <= 0) {
+            return std::vector<IntArrayView>();
+        }
+        std::vector<IntArrayView> result;
+        if (limit == 1) {
+            result.emplace_back(mPtr, mSize);
+            return result;
+        }
+        size_t startIndex = 0;
+        for (size_t i = 0; i < mSize; ++i) {
+            if (mPtr[i] == separator) {
+                result.emplace_back(mPtr + startIndex, i - startIndex);
+                startIndex = i + 1;
+                if (result.size() >= static_cast<size_t>(limit - 1)) {
+                    break;
+                }
+            }
+        }
+        result.emplace_back(mPtr + startIndex, mSize - startIndex);
+        return result;
+    }
+
  private:
     DISALLOW_ASSIGNMENT_OPERATOR(IntArrayView);
 
@@ -100,6 +165,9 @@ class IntArrayView {
 
 using WordIdArrayView = IntArrayView;
 using PtNodePosArrayView = IntArrayView;
+using CodePointArrayView = IntArrayView;
+template <size_t size>
+using WordIdArray = std::array<int, size>;
 
 } // namespace latinime
 #endif // LATINIME_MEMORY_VIEW_H
diff --git a/native/jni/src/utils/jni_data_utils.cpp b/native/jni/src/utils/jni_data_utils.cpp
index 5555293d5..41f0623d8 100644
--- a/native/jni/src/utils/jni_data_utils.cpp
+++ b/native/jni/src/utils/jni_data_utils.cpp
@@ -16,9 +16,100 @@
 
 #include "utils/jni_data_utils.h"
 
+#include "utils/int_array_view.h"
+
 namespace latinime {
 
 const int JniDataUtils::CODE_POINT_REPLACEMENT_CHARACTER = 0xFFFD;
 const int JniDataUtils::CODE_POINT_NULL = 0;
 
+/* static */ void JniDataUtils::outputWordProperty(JNIEnv *const env,
+        const WordProperty &wordProperty, jintArray outCodePoints, jbooleanArray outFlags,
+        jintArray outProbabilityInfo, jobject outNgramPrevWordsArray,
+        jobject outNgramPrevWordIsBeginningOfSentenceArray, jobject outNgramTargets,
+        jobject outNgramProbabilities, jobject outShortcutTargets,
+        jobject outShortcutProbabilities) {
+    const CodePointArrayView codePoints = wordProperty.getCodePoints();
+    JniDataUtils::outputCodePoints(env, outCodePoints, 0 /* start */,
+            MAX_WORD_LENGTH /* maxLength */, codePoints.data(), codePoints.size(),
+            false /* needsNullTermination */);
+    const UnigramProperty &unigramProperty = wordProperty.getUnigramProperty();
+    const std::vector<NgramProperty> &ngrams = wordProperty.getNgramProperties();
+    jboolean flags[] = {unigramProperty.isNotAWord(), unigramProperty.isPossiblyOffensive(),
+            !ngrams.empty(), unigramProperty.hasShortcuts(),
+            unigramProperty.representsBeginningOfSentence()};
+    env->SetBooleanArrayRegion(outFlags, 0 /* start */, NELEMS(flags), flags);
+    const HistoricalInfo &historicalInfo = unigramProperty.getHistoricalInfo();
+    int probabilityInfo[] = {unigramProperty.getProbability(), historicalInfo.getTimestamp(),
+            historicalInfo.getLevel(), historicalInfo.getCount()};
+    env->SetIntArrayRegion(outProbabilityInfo, 0 /* start */, NELEMS(probabilityInfo),
+            probabilityInfo);
+
+    jclass integerClass = env->FindClass("java/lang/Integer");
+    jmethodID intToIntegerConstructorId = env->GetMethodID(integerClass, "<init>", "(I)V");
+    jclass arrayListClass = env->FindClass("java/util/ArrayList");
+    jmethodID addMethodId = env->GetMethodID(arrayListClass, "add", "(Ljava/lang/Object;)Z");
+
+    // Output ngrams.
+    jclass intArrayClass = env->FindClass("[I");
+    for (const auto &ngramProperty : ngrams) {
+        const NgramContext *const ngramContext = ngramProperty.getNgramContext();
+        jobjectArray prevWordWordCodePointsArray = env->NewObjectArray(
+                ngramContext->getPrevWordCount(), intArrayClass, nullptr);
+        jbooleanArray prevWordIsBeginningOfSentenceArray =
+                env->NewBooleanArray(ngramContext->getPrevWordCount());
+        for (size_t i = 0; i < ngramContext->getPrevWordCount(); ++i) {
+            const CodePointArrayView codePoints = ngramContext->getNthPrevWordCodePoints(i + 1);
+            jintArray prevWordCodePoints = env->NewIntArray(codePoints.size());
+            JniDataUtils::outputCodePoints(env, prevWordCodePoints, 0 /* start */,
+                    codePoints.size(), codePoints.data(), codePoints.size(),
+                    false /* needsNullTermination */);
+            env->SetObjectArrayElement(prevWordWordCodePointsArray, i, prevWordCodePoints);
+            env->DeleteLocalRef(prevWordCodePoints);
+            JniDataUtils::putBooleanToArray(env, prevWordIsBeginningOfSentenceArray, i,
+                    ngramContext->isNthPrevWordBeginningOfSentence(i + 1));
+        }
+        env->CallBooleanMethod(outNgramPrevWordsArray, addMethodId, prevWordWordCodePointsArray);
+        env->CallBooleanMethod(outNgramPrevWordIsBeginningOfSentenceArray, addMethodId,
+                prevWordIsBeginningOfSentenceArray);
+        env->DeleteLocalRef(prevWordWordCodePointsArray);
+        env->DeleteLocalRef(prevWordIsBeginningOfSentenceArray);
+
+        const std::vector<int> *const targetWordCodePoints = ngramProperty.getTargetCodePoints();
+        jintArray targetWordCodePointArray = env->NewIntArray(targetWordCodePoints->size());
+        JniDataUtils::outputCodePoints(env, targetWordCodePointArray, 0 /* start */,
+                targetWordCodePoints->size(), targetWordCodePoints->data(),
+                targetWordCodePoints->size(), false /* needsNullTermination */);
+        env->CallBooleanMethod(outNgramTargets, addMethodId, targetWordCodePointArray);
+        env->DeleteLocalRef(targetWordCodePointArray);
+
+        const HistoricalInfo &ngramHistoricalInfo = ngramProperty.getHistoricalInfo();
+        int bigramProbabilityInfo[] = {ngramProperty.getProbability(),
+                ngramHistoricalInfo.getTimestamp(), ngramHistoricalInfo.getLevel(),
+                ngramHistoricalInfo.getCount()};
+        jintArray bigramProbabilityInfoArray = env->NewIntArray(NELEMS(bigramProbabilityInfo));
+        env->SetIntArrayRegion(bigramProbabilityInfoArray, 0 /* start */,
+                NELEMS(bigramProbabilityInfo), bigramProbabilityInfo);
+        env->CallBooleanMethod(outNgramProbabilities, addMethodId, bigramProbabilityInfoArray);
+        env->DeleteLocalRef(bigramProbabilityInfoArray);
+    }
+
+    // Output shortcuts.
+    for (const auto &shortcut : unigramProperty.getShortcuts()) {
+        const std::vector<int> *const targetCodePoints = shortcut.getTargetCodePoints();
+        jintArray shortcutTargetCodePointArray = env->NewIntArray(targetCodePoints->size());
+        JniDataUtils::outputCodePoints(env, shortcutTargetCodePointArray, 0 /* start */,
+                targetCodePoints->size(), targetCodePoints->data(), targetCodePoints->size(),
+                false /* needsNullTermination */);
+        env->CallBooleanMethod(outShortcutTargets, addMethodId, shortcutTargetCodePointArray);
+        env->DeleteLocalRef(shortcutTargetCodePointArray);
+        jobject integerProbability = env->NewObject(integerClass, intToIntegerConstructorId,
+                shortcut.getProbability());
+        env->CallBooleanMethod(outShortcutProbabilities, addMethodId, integerProbability);
+        env->DeleteLocalRef(integerProbability);
+    }
+    env->DeleteLocalRef(integerClass);
+    env->DeleteLocalRef(arrayListClass);
+}
+
 } // namespace latinime
diff --git a/native/jni/src/utils/jni_data_utils.h b/native/jni/src/utils/jni_data_utils.h
index cb82d3c3b..8024e34c4 100644
--- a/native/jni/src/utils/jni_data_utils.h
+++ b/native/jni/src/utils/jni_data_utils.h
@@ -20,10 +20,11 @@
 #include <vector>
 
 #include "defines.h"
+#include "dictionary/header/header_read_write_utils.h"
+#include "dictionary/interface/dictionary_header_structure_policy.h"
+#include "dictionary/property/ngram_context.h"
+#include "dictionary/property/word_property.h"
 #include "jni.h"
-#include "suggest/core/session/prev_words_info.h"
-#include "suggest/core/policy/dictionary_header_structure_policy.h"
-#include "suggest/policyimpl/dictionary/header/header_read_write_utils.h"
 #include "utils/char_utils.h"
 
 namespace latinime {
@@ -50,6 +51,7 @@ class JniDataUtils {
             const jsize keyUtf8Length = env->GetStringUTFLength(keyString);
             char keyChars[keyUtf8Length + 1];
             env->GetStringUTFRegion(keyString, 0, env->GetStringLength(keyString), keyChars);
+            env->DeleteLocalRef(keyString);
             keyChars[keyUtf8Length] = '\0';
             DictionaryHeaderStructurePolicy::AttributeMap::key_type key;
             HeaderReadWriteUtils::insertCharactersIntoVector(keyChars, &key);
@@ -59,6 +61,7 @@ class JniDataUtils {
             const jsize valueUtf8Length = env->GetStringUTFLength(valueString);
             char valueChars[valueUtf8Length + 1];
             env->GetStringUTFRegion(valueString, 0, env->GetStringLength(valueString), valueChars);
+            env->DeleteLocalRef(valueString);
             valueChars[valueUtf8Length] = '\0';
             DictionaryHeaderStructurePolicy::AttributeMap::mapped_type value;
             HeaderReadWriteUtils::insertCharactersIntoVector(valueChars, &value);
@@ -96,18 +99,14 @@ class JniDataUtils {
         }
     }
 
-    static PrevWordsInfo constructPrevWordsInfo(JNIEnv *env, jobjectArray prevWordCodePointArrays,
-            jbooleanArray isBeginningOfSentenceArray) {
+    static NgramContext constructNgramContext(JNIEnv *env, jobjectArray prevWordCodePointArrays,
+            jbooleanArray isBeginningOfSentenceArray, const size_t prevWordCount) {
         int prevWordCodePoints[MAX_PREV_WORD_COUNT_FOR_N_GRAM][MAX_WORD_LENGTH];
         int prevWordCodePointCount[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
         bool isBeginningOfSentence[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
-        jsize prevWordsCount = env->GetArrayLength(prevWordCodePointArrays);
-        for (size_t i = 0; i < NELEMS(prevWordCodePoints); ++i) {
+        for (size_t i = 0; i < prevWordCount; ++i) {
             prevWordCodePointCount[i] = 0;
             isBeginningOfSentence[i] = false;
-            if (prevWordsCount <= static_cast<int>(i)) {
-                continue;
-            }
             jintArray prevWord = (jintArray)env->GetObjectArrayElement(prevWordCodePointArrays, i);
             if (!prevWord) {
                 continue;
@@ -117,14 +116,15 @@ class JniDataUtils {
                 continue;
             }
             env->GetIntArrayRegion(prevWord, 0, prevWordLength, prevWordCodePoints[i]);
+            env->DeleteLocalRef(prevWord);
             prevWordCodePointCount[i] = prevWordLength;
             jboolean isBeginningOfSentenceBoolean = JNI_FALSE;
             env->GetBooleanArrayRegion(isBeginningOfSentenceArray, i, 1 /* len */,
                     &isBeginningOfSentenceBoolean);
             isBeginningOfSentence[i] = isBeginningOfSentenceBoolean == JNI_TRUE;
         }
-        return PrevWordsInfo(prevWordCodePoints, prevWordCodePointCount, isBeginningOfSentence,
-                MAX_PREV_WORD_COUNT_FOR_N_GRAM);
+        return NgramContext(prevWordCodePoints, prevWordCodePointCount, isBeginningOfSentence,
+                prevWordCount);
     }
 
     static void putBooleanToArray(JNIEnv *env, jbooleanArray array, const int index,
@@ -141,6 +141,12 @@ class JniDataUtils {
         env->SetFloatArrayRegion(array, index, 1 /* len */, &value);
     }
 
+    static void outputWordProperty(JNIEnv *const env, const WordProperty &wordProperty,
+            jintArray outCodePoints, jbooleanArray outFlags, jintArray outProbabilityInfo,
+            jobject outNgramPrevWordsArray, jobject outNgramPrevWordIsBeginningOfSentenceArray,
+            jobject outNgramTargets, jobject outNgramProbabilities, jobject outShortcutTargets,
+            jobject outShortcutProbabilities);
+
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(JniDataUtils);
 
diff --git a/native/jni/src/utils/ngram_utils.h b/native/jni/src/utils/ngram_utils.h
new file mode 100644
index 000000000..fa85ba35f
--- /dev/null
+++ b/native/jni/src/utils/ngram_utils.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_NGRAM_UTILS_H
+#define LATINIME_NGRAM_UTILS_H
+
+#include "defines.h"
+
+namespace latinime {
+
+enum class NgramType : int {
+    Unigram = 0,
+    Bigram = 1,
+    Trigram = 2,
+    Quadgram = 3,
+    NotANgramType = -1,
+};
+
+namespace AllNgramTypes {
+// Use anonymous namespace to avoid ODR (One Definition Rule) violation.
+namespace {
+
+const NgramType ASCENDING[] = {
+   NgramType::Unigram, NgramType::Bigram, NgramType::Trigram
+};
+
+const NgramType DESCENDING[] = {
+   NgramType::Trigram, NgramType::Bigram, NgramType::Unigram
+};
+
+}  // namespace
+}  // namespace AllNgramTypes
+
+class NgramUtils final {
+ public:
+    static AK_FORCE_INLINE NgramType getNgramTypeFromWordCount(const int wordCount) {
+        // Max supported ngram is (MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1)-gram.
+        if (wordCount <= 0 || wordCount > MAX_PREV_WORD_COUNT_FOR_N_GRAM + 1) {
+            return NgramType::NotANgramType;
+        }
+        // Convert word count to 0-origin enum value.
+        return static_cast<NgramType>(wordCount - 1);
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(NgramUtils);
+
+};
+}
+#endif /* LATINIME_NGRAM_UTILS_H */
diff --git a/native/jni/src/utils/profiler.h b/native/jni/src/utils/profiler.h
new file mode 100644
index 000000000..5f107fed3
--- /dev/null
+++ b/native/jni/src/utils/profiler.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_PROFILER_H
+#define LATINIME_PROFILER_H
+
+#ifdef FLAG_DO_PROFILE
+
+#include "defines.h"
+
+#include <ctime>
+#include <unordered_map>
+
+namespace latinime {
+
+class Profiler final {
+ public:
+    Profiler(const clockid_t clockId)
+            : mClockId(clockId), mStartTime(getTimeInMicroSec()), mStartTimes(), mTimes(),
+              mCounters() {}
+
+    ~Profiler() {
+        const float totalTime =
+                static_cast<float>(getTimeInMicroSec() - mStartTime) / 1000.f;
+        AKLOGI("Total time is %6.3f ms.", totalTime);
+        for (const auto &time : mTimes) {
+            AKLOGI("(%d): Used %4.2f%%, %8.4f ms. Called %d times.", time.first,
+                    time.second / totalTime * 100.0f, time.second, mCounters[time.first]);
+        }
+    }
+
+    void startTimer(const int id) {
+        mStartTimes[id] = getTimeInMicroSec();
+    }
+
+    void endTimer(const int id) {
+        mTimes[id] += static_cast<float>(getTimeInMicroSec() - mStartTimes[id]) / 1000.0f;
+        mCounters[id]++;
+    }
+
+    operator bool() const { return false; }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Profiler);
+
+    const clockid_t mClockId;
+    int64_t mStartTime;
+    std::unordered_map<int, int64_t> mStartTimes;
+    std::unordered_map<int, float> mTimes;
+    std::unordered_map<int, int> mCounters;
+
+    int64_t getTimeInMicroSec() {
+        timespec time;
+        clock_gettime(mClockId, &time);
+        return static_cast<int64_t>(time.tv_sec) * 1000000
+                + static_cast<int64_t>(time.tv_nsec) / 1000;
+    }
+};
+} // namespace latinime
+
+#define PROF_INIT Profiler __LATINIME__PROFILER__(CLOCK_THREAD_CPUTIME_ID)
+#define PROF_TIMER_START(timer_id) __LATINIME__PROFILER__.startTimer(timer_id)
+#define PROF_TIMER_END(timer_id) __LATINIME__PROFILER__.endTimer(timer_id)
+
+#else // FLAG_DO_PROFILE
+
+#define PROF_INIT
+#define PROF_TIMER_START(timer_id)
+#define PROF_TIMER_END(timer_id)
+
+#endif // FLAG_DO_PROFILE
+
+#endif /* LATINIME_PROFILER_H */