Alignment Based Neural Machine Translation
Neural machine translation (NMT) has emerged recently as a promising statistical machine translation approach. In NMT, neural networks (NN) are directly used to produce translations, without relying on a pre existing translation framework. In this work, we take a step towards bridging the gap between conventional word alignment models and NMT. We follow the hidden Markov model (HMM) approach that separates the alignment and lexical models. We propose a neural alignment model and combine it with a lexical neural model in a loglinear framework. The models are used in a standalone word based decoder that explicitly hypothesizes alignments during search. We demonstrate that our system outperforms attention based NMT on two tasks: IWSLT 2013 German English and BOLT Chinese English. We also show promising results for re aligning the training data using neural models.
WMT