Construction of Corpus-Based Syntactic Rules for Accurate Speech Recognition

This paper describes the syntactic rules which are applied in the Japanese speech recognition module of a speech-to-speech translation system. Japanese is considered to be a free word/phrase order language. Since syntactic rules are applied as constraints to reduce the search space in speech recognition, applying rules which take into account all possible phrase orders can have almost the same effect as using no constraints. Instead, we take into consideration the recognition weaknesses of certain syntactic categories and treat them precisely, so that a minimal number of rules can work most effectively. In this paper we first examine which syntactic categories are easily misrecognized. Second, we consult our dialogue corpus, in order to provide the rules with great generality. Based on both studies, we refine the rules. Finally, we verify the validity of the refinement through speech recognition experiments.