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diff --git a/native/jni/src/dictionary/utils/multi_bigram_map.cpp b/native/jni/src/dictionary/utils/multi_bigram_map.cpp
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+++ b/native/jni/src/dictionary/utils/multi_bigram_map.cpp
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+/*
+ * 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/utils/multi_bigram_map.h"
+
+#include <cstddef>
+#include <unordered_map>
+
+namespace latinime {
+
+// Max number of bigram maps (previous word contexts) to be cached. Increasing this number
+// could improve bigram lookup speed for multi-word suggestions, but at the cost of more memory
+// usage. Also, there are diminishing returns since the most frequently used bigrams are
+// typically near the beginning of the input and are thus the first ones to be cached. Note
+// that these bigrams are reset for each new composing word.
+const size_t MultiBigramMap::MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP = 25;
+
+// Most common previous word contexts currently have 100 bigrams
+const int MultiBigramMap::BigramMap::DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP = 100;
+
+// 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 MultiBigramMap::getBigramProbability(
+        const DictionaryStructureWithBufferPolicy *const structurePolicy,
+        const WordIdArrayView prevWordIds, const int nextWordId,
+        const int unigramProbability) {
+    if (prevWordIds.empty() || prevWordIds[0] == NOT_A_WORD_ID) {
+        return structurePolicy->getProbability(unigramProbability, NOT_A_PROBABILITY);
+    }
+    const auto mapPosition = mBigramMaps.find(prevWordIds[0]);
+    if (mapPosition != mBigramMaps.end()) {
+        return mapPosition->second.getBigramProbability(structurePolicy, nextWordId,
+                unigramProbability);
+    }
+    if (mBigramMaps.size() < MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP) {
+        addBigramsForWord(structurePolicy, prevWordIds);
+        return mBigramMaps[prevWordIds[0]].getBigramProbability(structurePolicy,
+                nextWordId, unigramProbability);
+    }
+    return readBigramProbabilityFromBinaryDictionary(structurePolicy, prevWordIds,
+            nextWordId, unigramProbability);
+}
+
+void MultiBigramMap::BigramMap::init(
+        const DictionaryStructureWithBufferPolicy *const structurePolicy,
+        const WordIdArrayView prevWordIds) {
+    structurePolicy->iterateNgramEntries(prevWordIds, this /* listener */);
+}
+
+int MultiBigramMap::BigramMap::getBigramProbability(
+        const DictionaryStructureWithBufferPolicy *const structurePolicy,
+        const int nextWordId, const int unigramProbability) const {
+    int bigramProbability = NOT_A_PROBABILITY;
+    if (mBloomFilter.isInFilter(nextWordId)) {
+        const auto bigramProbabilityIt = mBigramMap.find(nextWordId);
+        if (bigramProbabilityIt != mBigramMap.end()) {
+            bigramProbability = bigramProbabilityIt->second;
+        }
+    }
+    return structurePolicy->getProbability(unigramProbability, bigramProbability);
+}
+
+void MultiBigramMap::BigramMap::onVisitEntry(const int ngramProbability, const int targetWordId) {
+    if (targetWordId == NOT_A_WORD_ID) {
+        return;
+    }
+    mBigramMap[targetWordId] = ngramProbability;
+    mBloomFilter.setInFilter(targetWordId);
+}
+
+void MultiBigramMap::addBigramsForWord(
+        const DictionaryStructureWithBufferPolicy *const structurePolicy,
+        const WordIdArrayView prevWordIds) {
+    mBigramMaps[prevWordIds[0]].init(structurePolicy, prevWordIds);
+}
+
+int MultiBigramMap::readBigramProbabilityFromBinaryDictionary(
+        const DictionaryStructureWithBufferPolicy *const structurePolicy,
+        const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability) {
+    const int bigramProbability = structurePolicy->getProbabilityOfWord(prevWordIds, nextWordId);
+    if (bigramProbability != NOT_A_PROBABILITY) {
+        return bigramProbability;
+    }
+    return structurePolicy->getProbability(unigramProbability, NOT_A_PROBABILITY);
+}
+
+} // namespace latinime