On sentential effects in the control of segmental duration in Japanese

Mainly, only word level factors, such as the temporal compensation between neighboring segments, have been used for duration control in the speech synthesis of Japanese. In this paper, the durational characteristics of Japanese are analyzed aiming at a higher level control, which reflects also sentential effects on segmental duration. First, the word level control was formulated as a linear additive model influenced by neighboring segments, location in a word, and word length. The parameters of the formula needed to integrate these features were obtained through factor analysis on a large‐scale isolated word data base (5240 words). An experiment using 216 words showed that the formula was more accurate than the conventional method. Second, focusing on sentential effects could be accomplished by comparing the predicted with the measured durations of continuous speech. The prediction errors clarified the following characteristics of sentence level duration control. (1) Prepausal lengthening is greater than ...