Tonal Ambiguity in Mandarin

Variation in tone fundamental frequency in Mandarin has long attracted intensive research focusing on the underlying factors that affect tonal shape. The current paper focuses on tone f0 shape different modes of speech and presents our results delineating the diversity of tonal f0 contour and how contextual elements affect realized tone shape in an acoustic environment with high variance of tonal shape. The current paper compares prosodic realizations of Mandarin tones in different speech modes, focusing on Tone 1 and Tone 4 to explore the tonal variability and the degree of f0 contour overlap. Our results find substantial overlap between these two tones among speakers and across different modes of speech. We identify several determinants of divergence and adherence to tonal defined shapes, and further find that speech mode is a critical element in acoustic ambiguity and in the degree of tonal f0 contour overlap in spoken Mandarin.