Speech Science Forum 11th February - Dr. Jason Shaw

Title: Gestural coordination in the living lexicon of spoken words.

Abstract:

Language varieties show variety-specific patterns of gestural coordination, where gestures are forces (dynamics) that exert control over articulatory movements (kinematics), see, e.g., Browman & Goldstein (1986). By hypothesis, the dimensions of gestural control are those that serve phonological function, e.g., supporting contrast in the lexicon. I start by illustrating this point with a comparison of Russian palatalized consonants, e.g., /p^j/, /b^j/, /m^j/, with articulatorily similar English sequences /pj/, /bj/, /mj/. High temporal resolution articulatory tracking, using Electromagnetic Articulography (EMA), reveals systematic differences in coordination corresponding to differing phonological functions: complex segments (Russian) vs. segment sequences (English). I next present cases in which linguistic context conditions systematic changes in gestural coordination. First, in Tokyo Japanese, high vowel devoicing can trigger the categorical loss of a lingual gesture for the vowel and subsequent reorganization of gestural coordination (Shaw & Kawahara 2018, 2021). Second, in Mandarin Chinese, certain morpho-syntactic environments condition a shift in gestural timing, which shortens syllable duration and precipitates a loss of lexical tone. This last case is particularly informative when compared with diaspora Tibetan, where tone loss has proceeded without gestural reorganization (Geissler et al., 2021). These patterns are consistent with a characterization of the human lexicon in terms of a relatively small number of gestures and coordination modes, organized to support phonological function and sensitive to linguistic context.  I close by presenting two additional cases, also drawn from Mandarin and Japanese, that challenge the completeness of this view of the lexicon, showing both (1) that the lexicon absorbs contextual prosodic influences, leading to gradient shifts in phonetic form (Tang & Shaw, 2021) and (2) that the phonetic form of words can resist influences of prosodic context (Kawahara, Shaw, Ishihara, 2021). Taken together, these data suggest that a low dimensional characterization of the lexicon in terms of discrete gestures and coordination modes co-exists with a representation of higher dimensional phonetic parameterization.