Publication Data
Fast and Scalable Decoding with Language Model Look-Ahead for Phrase-based Statistical Machine Translation
Abstract: In this work we present two extensions to the well-known
dynamic programming beam search in phrase-based statistical machine translation (SMT),
aiming at increased effi- ciency of decoding by minimizing the number of language model
computations and hypothesis expansions. Our results show that language model based
pre-sorting yields a small improvement in translation quality and a speedup by a factor
of 2. Two look-ahead methods are shown to further increase translation speed by a
factor of 2 without changing the search space and a factor of 4 with the side-effect of
some additional search errors. We compare our approach with Moses and observe the same
performance, but a substantially better trade-off between translation quality and
speed. At a speed of roughly 70 words per second, Moses reaches 17.2% BLEU, whereas our
approach yields 20.0% with identical models.
