Abstract

Neural machine translation (NMT) models typically operate with a fixed vocabulary, but translation is an open-vocabulary problem.Previous work addresses the translation of out-of-vocabulary words by backing off to a dictionary.In this paper, we introduce a simpler and more effective approach, making the NMT model capable of open-vocabulary translation by encoding rare and unknown words as sequences of subword units.This is based on the intuition that various word classes are translatable via smaller units than words, for instance names (via character copying or transliteration), compounds (via compositional translation), and cognates and loanwords (via phonological and morphological transformations).We discuss the suitability of different word segmentation techniques, including simple character ngram models and a segmentation based on the byte pair encoding compression algorithm, and empirically show that subword models improve over a back-off dictionary baseline for the WMT 15 translation tasks English→German and English→Russian by up to 1.1 and 1.3 BLEU, respectively.

Keywords

Machine translationComputer scienceTranslation (biology)Natural language processingArtificial intelligenceTransfer-based machine translationExample-based machine translationSpeech recognitionChemistry

Affiliated Institutions

Related Publications

Publication Info

Year
N/A
Type
article
Citations
6994
Access
Closed

External Links

Citation Metrics

6994
OpenAlex

Cite This

Rico Sennrich, Barry Haddow, Alexandra Birch (n.d.). . Edinburgh Research Explorer (University of Edinburgh) .