Creaky Voice as a Function of Tonal Categories and Prosodic Boundaries

This study looks into the distribution of creaky voice in Mandarin in continuous speech. A creaky voice detector was used to automatically detect the appearance of creaky voice in a large-scale Mandarin corpus (Sinica COSPRO corpus). As the prosodic information has been annotated in the corpus, we were able to look at the distribution of creaky voice as a function of the interaction between tone and prosodic structures. As expected, among the five tonal categories (four lexical tones and one neutral tone), creaky voice is most likely to occur with Tone 3 and the neutral tone, followed by Tone 2 and Tone 4. Prosodic boundaries also play important roles, as the likelihood of creak increases when the prosodic boundaries are larger, regardless of the tonal categories. It is also confirmed that the pitch range for the occurrence of creaky voice is 110 Hz for male speakers and 170 Hz for female speakers, consistent with previous small-scale studies. Finally, male speakers have a higher overall rate of creaky voice than female speakers. Altogether, this study validates the hypotheses from previous studies, and provides a better understanding of voice-source variation in different prosodic conditions.