Hierarchical Mt Training Using Max-Violation Perceptron

Large-scale discriminative training has become promising for statistical machine translation by leveraging the huge training corpus; for example the recent effort in phrase-based MT (Yu et al., 2013) significantly outperforms mainstream methods that only train on small tuning sets. However, phrase-based MT suffers from limited reorderings, and thus its training can only utilize a small portion of the bi-text due to the distortion limit. To address this problem, we extend Yu et al. (2013) to syntax-based MT by generalizing their latent variable "violation-fixing" perceptron from graphs to hypergraphs. Experiments confirm that our method leads to up to +1.2 BLEU improvement over mainstream methods such as MERT and PRO.