Post-Ordering by Parsing with ITG for Japanese-English Statistical Machine Translation

摘要

Word reordering is a difficult task for translation between languages with widely different word orders, such as Japanese and English. A previously proposed post-ordering method for Japanese-to-English translation first translates a Japanese sentence into a sequence of English words in a word order similar to that of Japanese, then reorders the sequence into an English word order. We employed this post-ordering framework and improved upon its reordering method. The existing post-ordering method reorders the sequence of English words via SMT, whereas our method reorders the sequence by (1) parsing the sequence using ITG to obtain syntactic structures which are similar to Japanese syntactic structures, and (2) transferring the obtained syntactic structures into English syntactic structures according to the ITG. The experiments using Japanese-to-English patent translation demonstrated the effectiveness of our method and showed that both the RIBES and BLEU scores were improved over compared methods.