Generation of F0 contours for Vietnamese speech synthesis

This paper describes the analysis results about the influence of coarticulation effect and syllable duration on variations of Vietnamese tones in continuous speech. Based on these results a new method for generating F0 contours is proposed. Firstly the contour of tonal register, which is calculated from relative register ratios between two adjacent tones, is produced. And then the tone patterns are superimposed on it. The first results based on a perceptual test show that the coarticulation effect plays an important role for generating a high quality synthetic speech in Vietnamese.