Quantitative and structural modeling of voice fundamental frequency contours of speech in Mandarin

This paper presents an approach to structural modeling of voice fundamental frequency contours (F0 contours) of Mandarin utterances as a sequence of modulated tones. A proposed functional model mathematically implements the tone modulation with both local and global controls. The local control consists of placing a series of normalized F0 targets along the time axis, which are specified by transition time and amplitudes and are always reached; and the transitions between targets are approximated by connecting truncated second-order transition functions. The global control in terms of sentence modality simply compresses or expands the heights and ranges of the prototypical patterns of syllabic tones generated by the local control. Both local and global controls are integrated in a unified framework, and this paper explains the underlying scientific and linguistic principles. Analysis of 1044 utterances of various sentences read by eight native speakers revealed that the model could closely approximate the observed F0 contours with a small number of parameters. These parameters are localized and suited to a data-driven fitting process. As will be demonstrated, the model also is promising for measuring intonation variations from observed F0 contours.