Using polysyllabic units for text to speech synthesis in Indian languages

This paper describes the design and development of Indian language Text-To-Speech (TTS) synthesis systems, using polysyllabic units. Firstly, a phone based TTS is built. Later, a monosyllable cluster unit TTS is built. It is observed that the quality of the synthesized sentences can improve if polysyllable units are used (when the appropriate units are available), since the effects of co-articulation will be preserved in such a case. Hence, we built Hindi and Tamil TTS with polysyllabic units, that contains cluster units of more than one type (monosyllable, bisyllable and trisyllable). The system selects the best set of units during the unit selection process, so as to minimize the join and concatenation costs. Preliminary listening tests indicated that the polysyllable TTS has better quality.