Design and Evaluation of a Persian TTS system using prosodically-sensitive concatenative units

This paper describes the design and evaluation of prosodically-sensitive concatenative units for a Persian text-to-speech (TTS) synthesis system. Thesyllables used are prosodically conditioned in the sense that a single conventional syllable is stored as different versions taken directly from the different prosodic domains of the prosodically labeled, read sentences. The three levels of the Persian prosodic hierarchy were observed in the syllable selection process, thereby selecting three different versions of each syllable from the prosodic domains of the intonational phrase (IP), accentual phrase (AP) and prosodic word (PW). A listening experiment designed to evaluate the quality of the syllable database showed that listeners preferred stimuli composed of prosodically appropriate diphones. We interpret this as supporting the view that segments carry prosodic domain information.