Information for Mandarin Tones in the Amplitude Contour and in Brief Segments

While the tones of Mandarin are conveyed mainly by the F0 contour, they also differ consistently in duration and in amplitude contour. The contribution of these factors was examined by using signal-correlated noise stimuli, in which natural speech is manipulated so that it has no F0 or formant structure but retains its original amplitude contour and duration. Tones 2, 3 and 4 were perceptible from just the amplitude contour, even when duration was not also a cue. In two further experiments, the location of the critical information for the tones during the course of the syllable was examined by extracting small segments from each part of the original syllable. Tones 2 and 3 were often confused with each other, and segments which did not have much F0 change were most often heard as Tone 1. There were, though, also cases in which a low, unchanging pitch was heard as Tone 3, indicating a partial effect of register even in Mandarin. F0 was positively correlated with amplitude, even when both were computed on a pitch period basis. Taken together, the results show that Mandarin tones are realized in more than just the F0 pattern, that amplitude contours can be used by listeners as cues for tone identification, and that not every portion of the F0 pattern unambiguously indicates the original tone.