A framework of reply speech generation for concept-to-speech conversion in spoken dialogue systems

Due to recent advancements in speech technologies, a large number of spoken dialogue systems have been constructed. However, since most of them adopt existing text-to-speech synthesizers, it is rather difficult to reflect the linguistic information obtained during the reply sentence generation well in output speech. A framework is necessary for correctly reflecting higher-level linguistic information, such as syntactic structure and discourse information. We have constructed a spoken dialogue system on road guidance and realized concept-to-speech conversion, where output speech is generated in a unified process. Tag LISP forms keep the syntactic structures throughout the process in order to reflect the linguistic information in the prosody of output speech. Furthermore, by making it possible to insert not only words but also phrase templates in tags, various sentences were generated with a minor increase of templates. Validity of the methods is shown through experiments.