Integration of rule-based formant synthesis and waveform concatenation: a hybrid approach to text-to-speech synthesis

This paper describes an approach to speech synthesis in which waveform fragments dynamically produced with a set of formant-based synthesis rules are concatenated with pre-stored natural speech waveform fragments to produce a synthetic utterance. While this hybrid approach was originally implemented as a tool for research into improved voice quality in formant-based synthesis, it has produced such good results that we now view it as a potentially viable and advantageous approach for a text-to-speech product. Possible advantages of the approach include smaller speech databases for waveform concatenation, enhancement of certain speech cues for sub-optimal listening environments, and improved and more efficient unit selection/production. In addition, the approach has already proven its utility as a tool for research and development in both concatenative and formant-based synthesis.