Extracting Pre-ordering Rules from Chunk-based Dependency Trees for Japanese-to-English Translation.
Xianchao Wu, Katsuhito Sudoh, Kevin Duh, Hajime Tsukada, Masaaki Nagata · 2011
Word ordering remains as an essential problem for translating between languages with substantial structural differences, such as SOV and SVO languages. In this paper, we propose to use source chunk-based dependency trees to extract pre-ordering rules, which are customized for translating from Japanese (SOV) to English (SVO). In order to obtain a finegrained classification of the reordering phenomena, Japanese function words and punctuation marks are included in the pre-ordering rules as additional lexical clues. We further prune the pre-ordering rule set by referring the predicate-argument structures of the target language side. Experimental results are reported for large-scale Japanese-to-English translation, showing a significant improvement of 1.48 BLEU points compared with the baseline SMT system. 1