Reordering model using syntactic information of a source tree for statistical machine translation

  • Authors:
  • Kei Hashimoto;Hirohumi Yamamoto;Hideo Okuma;Eiichiro Sumita;Keiichi Tokuda

  • Affiliations:
  • Nagoya Institute of Technology, Nagoya-city, Aichi, Japan;National Institute of Information and Communications Technology and Kinki University;National Institute of Information and Communications Technology and Spoken Language Communication Research Labs;National Institute of Information and Communications Technology and Spoken Language Communication Research Labs;Nagoya Institute of Technology, Nagoya-city, Aichi, Japan and National Institute of Information and Communications Technology

  • Venue:
  • SSST '09 Proceedings of the Third Workshop on Syntax and Structure in Statistical Translation
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

This paper presents a reordering model using syntactic information of a source tree for phrase-based statistical machine translation. The proposed model is an extension of ISTITG (imposing source tree on inversion transduction grammar) constraints. In the proposed method, the target-side word order is obtained by rotating nodes of the source-side parse-tree. We modeled the node rotation, monotone or swap, using word alignments based on a training parallel corpus and sourceside parse-trees. The model efficiently suppresses erroneous target word orderings, especially global orderings. Furthermore, the proposed method conducts a probabilistic evaluation of target word reorderings. In English-to-Japanese and English-to-Chinese translation experiments, the proposed method resulted in a 0.49-point improvement (29.31 to 29.80) and a 0.33-point improvement (18.60 to 18.93) in word BLEU-4 compared with IST-ITG constraints, respectively. This indicates the validity of the proposed reordering model.