Zero Pronoun Resolution can Improve the Quality of J-E Translation

In Japanese, particularly, spoken Japanese, subjective, objective and possessive cases are very often omitted. Such Japanese sentences are often translated by Japanese-English statistical machine translation to the English sentence whose subjective, objective and possessive cases are omitted, and it causes to decrease the quality of translation. We performed experiments of J-E phrase based translation using Japanese sentence, whose omitted pronouns are complemented by human. We introduced ‘antecedent F-measure’ as a score for measuring quality of the translated English. As a result, we found that it improves the scores of antecedent F-measure while the BLEU scores were almost unchanged. Every effectiveness of the zero pronoun resolution differs depending on the type and case of each zero pronoun.