Effects of tone and focus on the formation and alignment of f0 contours

The present study examines how lexical tone and focus contribute to the formation and alignment off, contours in speech. This was done through an investigation of f(0) contour formation in short Mandarin sentences. These sentences all consisted of five syllables with varying tones on the middle three syllables. The sentences were produced by eight Mandarin speakers with four different focus patterns: focus on the first, second, or last word, or with no narrow focus. The f(0) patterns of these sentences were examined through point-by-point f(0) tracing, graphical comparison of averaged f(0) contours, f(0)-contour-syllable alignment analysis, and analysis of maximum, minimum f(0), and slope of f(0) contours. The results indicate that (a) while the lexical tone of a syllable is the most important determining factor for the local f(0) contour of the syllable, focus extensively modulates the global shape of the f(0) curve, which in turn affects the height and even the shape of local contours; (b) the tones of adjacent syllables also extensively influence both the shape and height of the f(0) contour of a syllable, with the preceding tone exerting more influence than the following tone; (c) despite extensive variations in shape and height, the f(0) contour of a tone remains closely aligned with the associated syllable; and (d) both focus and tonal interaction may generate substantial f(0) decline over the course of an utterance. These findings seem to be able to reduce the unpredictability in the formation and alignment of f(0) contours in speech. (C) 1999 Academic Press.