Integration of Speech Recognition and Language Processing in a Japanese to English Spoken Language Translation System

Tsuyoshi MORIMOTO  Kiyohiro SHIKANO  Kiyoshi KOGURE  Hitoshi IIDA  Akira KUREMATSU  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E74-A   No.7   pp.1889-1896
Publication Date: 1991/07/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Issue on Continuous Speech Recognition and Understanding)
Category: Speech Understanding

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The experimental spoken language translation system (SL-TRANS) has been implemented. It can recognize Japanese speech, translate it to English, and output a synthesized English speech. One of the most important problems in realizing such a system is how to integrate, or connect, speech recognition and language processing. In this paper, a new method realized in the system is described. The method is composed of three processes: grammar-driven predictive speech recognition, Kakariuke-dependency-based candidate filtering, and HPSG-based lattice parsing which is supplemented with a sentence preference mechanism. Input speech is uttered phrase by phrase. The speech recognizer takes an input phrase utterance and outputs several candidates with recognition scores for each phrase. Japanese phrasal grammar is used in recognition. It contributes to the output of grammatically well-formed phrase candidates, as well as to the reduction of phone perplexity. The candidate filter takes a phrase lattice, which is a sequence of multiple candidates for a phrase, and outputs a reduced phrase lattice. It removes semantically inappropriate phrase candidates by applying the Kakariuke dependency relationship between phrases. Finally, the HPSG-based lattice parser takes a phrase lattice and chooses the most plausible sentence by checking syntactic and semantic legitimacy or evaluating sentential preference. Experiment results for the system are also reported and the usefulness of the method is confirmed.