Christian DiCanio Colloquium

November 12
3:30 - 5:00 pm
University of Buffalo
Tonal dissimilation and dispersion in speech production
Phonetic targets in speech production vary substantially by context. Speech produced in isolation or laboratory settings is characterized by careful articulations and an idealized set of articulatory and acoustic targets that a talker is able to produce. This same talker may be unable to produce these targets when speaking quickly or when a particular segment is influenced by its surrounding phonetic context (coarticulation). Coarticulatory patterns are typically assimilatory, whereby a speech sound changes to resemble its surrounding context. However, dissimilatory coarticulation also occurs, whereby a speech sound diverges either articulatorily or acoustically from its adjacent context. What is the cause of dissimilatory patterns like these and why might they occur?
Dissimilation is typically difficult to observe with respect to segmental coarticulation, but easier to observe in tone production. In this talk, I present experimental data from Itunyoso Triqui, an indigenous tonal language of Mexico where processes of tonal dissimilation are observed. The results show that (a) a greater tonal distance between successive tones produces increased dissimilation and (b) an increase in speech rate contributes to a general process of tonal range expansion, contra previous work (Xu 1994). While the former results fit within a model of speech production planning which gradiently inhibits the selection of local exemplars by context (Tilsen 2013), the latter results point to a more general process which maximizes tonal dispersion. For languages with a crowded tonal space like Triqui, these two mechanisms operate in tandem to preserve tonal contrast in a phonological system where it has a high functional load.
 
References:
Tilsen, S. (2013). Inhibitory mechanisms in speech planning maintain and maximize contrast. In Yu, A., editor, Origins of Sound Change: Approaches to Phonologization. Oxford University Press.
Xu, Y. (1994). Production and perception of coarticulated tones. Journal of the Acoustical Society of America, 96(4):2240–2253.