Identifying and Utilizing the Class of Monosemous Japanese Functional Expressions in Machine Translation

In the “Sandglass” machine translation architecture, we identify the class of monosemous Japanese functional expressions and utilize it in the task of translating Japanese functional expressions into English. We employ the semantic equivalence classes of a recently compiled large scale hierarchical lexicon of Japanese functional expressions. We then study whether functional expressions within a class can be translated into a single canonical English expression. Next, we introduce two types of ambiguities of functional expressions and identify monosemous functional expressions. In the evaluation of our translation rules for Japanese functional expressions, we directly apply those rules to monosemous functional expressions, and show that the proposed framework outperforms commercial machine translation software products. We further study how to extract rules for translating functional expressions in Japanese patent documents into English. In the result of this study, we show that translation rules manually developed based on the corpus for Japanese language grammar learners is reliable also in the patent domain.