The Acoustic Realization of Mandarin Tones in Fast Speech

Many studies have demonstrated that acoustic contrasts between speech segments (vowels and consonants) were reduced when speaking rate increases, while it was unclear whether tones in tonal languages also undergo similar modifications. Mandarin Chinese is a tonal language, while results regarding the rate effect on Mandarin tones in previous studies were mixed, probably driven by the material difference, i.e., the position of target tones within a sentence. Therefore, the present study examined the effect of speaking rate on Mandarin tones, comparing the pitch contour and tonal contrast of Mandarin tones between normal and fast speech across utterance initial, medial and final positions. The results showed that, relative to normal speech, lexical tones in Mandarin Chinese exhibited overall higher and flatter pitch contours, with smaller tonal space. Moreover, the rate effect on tones did not vary with position. The current results and previous studies on segments thus revealed a universal pattern of speech reduction in fast speech at both segmental and suprasegmental levels.