Different attributes of creaky voice distinctly affect Mandarin tonal perception

Previous work has shown mixed findings concerning the role of voice quality cues in Mandarin tones, with some studies showing that creak improves identification. This study tests the linguistic importance of acoustic properties of creak for Mandarin tone perception. Mandarin speakers identified tones with four resynthesized creak manipulations: low spectral tilt, irregular F0, period doubling, and extra-low F0. Two experiments with three conditions were conducted. In Experiment 1, the manipulations were confined to a portion of the stimuli's duration; in Experiment 2 the creak manipulations were modified and lengthened throughout the stimuli, and in a second condition, noise was incorporated to weaken F0 cues. Listeners remained most sensitive to extra-low F0, which affected identification of the four tones differently: it improved the identification accuracy of Tone 3 and hindered that of Tones 1 and 4. Irregular F0 consistently hindered T1 identification. The effects of irregular F0, period doubling, and low spectral tilt emerged in Experiment 2, where F0 cues were less robust and creak cues were stronger. Thus, low F0 is the most prominent cue used in Mandarin tone identification, but other voice quality cues become more salient to listeners when the F0 cues are less retrievable.