Automatic transcription of parliamentary meetings and classroom lectures - A sustainable approach and real system evaluations -

Applications of automatic speech recognition (ASR) have been extended to a variety of tasks and domains, including spontaneous human-human speech. We have developed an ASR system for the Japanese Parliament (Diet), which is deployed this year. By exploiting official records made by human stenographers, we have realized an efficient training scheme of acoustic and language models, which does not require faithful transcripts and thus is scalable to enormous data. Evaluation results of the semi-automated model update are presented. We are also working on an ASR system for classroom lectures, which is intended for assisting hearing impaired students. As the classroom lectures in universities are very technical, efficient adaptation methods of acoustic and language models are investigated. A trial of realtime captioning for a hearing impaired student in our university is reported.