Effects of pitch range variation on f0 extrema in an imitation task

A central issue in speech intonation research concerns how fundamental frequency (f0) variation relates to phonological categories. The hypothesis was tested that pitch range variation which affects whether one syllable is higher or lower than another would elicit categorical shifts in f0 extremum timing in an imitation task. Participants heard synthetic versions of the phrase Some lemonade with rising-falling or falling-rising intonation and flat f0 contours across le- and mo-. The f0 levels of le- and mo- were varied such that for half the stimuli, le- had a higher f0 than mo-, while the reverse was true for the remainder. Participants produced f0 peaks and valleys on syllables that had flat f0 in stimuli; extremum types (peaks or valleys) and their temporal alignments varied categorically with the relative f0 levels of le- and mo- in the stimuli. The results are discussed in terms of theories of intonational phonology. It is shown that an account of these results under autosegmental-metrical theory (e.g., Pierrehumbert, J. (1980). The phonology and phonetics of English intonation. Ph.D. dissertation, MIT, Cambridge, MA) requires positing additional constraints in phonetic models of f0. A revised version of the Pierrehumbert and Beckman [(1988). Japanese tone structure. Cambridge, MA: MIT Press] phonetic model is therefore proposed which assumes additional constraints on relative tone heights and strictly monotonic interpolation between tones.