Generation of prosodic symbols for rule-synthesis of connected speech of Japanese

In a text-to-speech conversion system, the prosodic features of speech should be synthesized strictly by rules. In order to construct a set of rules to generate the symbols for the prosodic features, such as the pause duration, the phrase command magnitude, and the accent command amplitude, speech samples of Japanese texts were analyzed quantitatively using the model for fundamental frequency contour generation. The analysis made clear the relationships between the prosodic features and the linguistic information, such as the accent type of a word, the syntactic structure of a sentence, and the discourse structure of a text. Based on these relationships, rules were constructed which generate the prosodic symbols from the linguistic information. Text-to-speech conversion was conducted using these rules. The naturalness of the intonation of the synthesized speech indicated the validity of the rules.