Modeling the effects of emphasis and question on fundamental frequency contours of Cantonese utterances

Emphasis and question are two factors that have significant effects on F-0 contours for various languages, among which tone languages require more careful study because their F-0 contours show complex interaction between lexical tones and sentence intonation. This paper employs the command-response model for the process of F-0 contour generation to investigate the effects of these two factors for Cantonese, a typical tone language with nine tones. Analysis shows that the major effect of emphasis is on phrase commands, whereas the polarity and the amplitude of the tone commands in the emphasized part are hardly affected so that the inherent tone command patterns are maintained. In the intonation question, the inherent tone command in the later part of the sentence-final syllable is always substituted by a positive tone command. The particle question, on the other hand, maintains the inherent tone command for the question particle. In both types of questions, a sentence-final phrase command is added or enhanced, and a particular ending tone command is attached, the amplitude of which can indicate the degree of inquisitive intention. By comparison, the effect of emphasis starts from the target part for emphasis but is not confined to it, whereas the effect of question is localized in the sentence-final part and especially concentrated within the ending syllable. Nevertheless, both of them can be represented in the framework of the command-response model, by which Fo contours for expressive speech can be generated efficiently.