Prosody Modeling from Tone to Intonation in Chinese using a Functional F0 Model

Chinese is a tonal language. It has both lexical tones and intonation. The fundamental frequency (F₀) contours thereby consist of tone and intonation components. This paper presents an approach to modeling the two components in separate ways and combining them to form the final F₀ contours based on a functional F₀ model. We analyze tonal patterns as sparse target points (tonal F₀ peaks and valleys) and model them using classification and regression trees (CART) with contextual linguistic features. As a first step, we stylize expressive intonation using a few piecewise linear patterns specified by a few markup tags. Both tonal and intonational patterns are represented in a parametric form within the framework of this F₀ model. Our experimental results indicated that very low F₀ prediction errors were achieved by the CART-based modeling of the tonal patterns uttered by two female and male speakers. In a listening test, the native speakers could identify 90% of synthesized stimuli with enhancing emphasis in word. Also, the linguistic features related to the lexical tone context and distinction between voiced and unvoiced initials played the most important role in characterizing the tonal patterns.