Abstract:

Prosodic boundary gestures or “pi‐gestures” (Byrd and Saltzman, J. Phonetics, 2003) have been introduced to model the local slowing or lengthening of articulatory gestures in the vicinity of phrase boundaries. Computational modeling of articulatory dynamics is an important tool in assessing the predicted effects of pi‐gestures of varying boundary strength on constriction gestures in varying contexts. We simulate pi‐gestures within the TaDA task dynamics computational model [Nam and Kim, JASA, 116, 172–185 (2004)] and examine how functional data analysis can provide a tool for connecting articulatory lengthening with underlying pi‐gesture activation strength. Specifically, the model is applied to the articulatory synthesis of two sequences: [CV#CV] and [CVC#CV], where C is bilabial or alveolar. The pi‐gesture’s midpoint is coordinated synchronously with the midpoint of following consonant’s constriction gesture, and pi‐gesture activation strength and duration are manipulated. Results indicate that pi‐gesture activation strength has a much stronger effect on slowing than its duration. The slowing effect is asymmetrical, skewed earlier than the midpoint in the pi‐gesture interval. After removing linear‐time slowing effect (i.e., after length normalization), the slowing effect is slightly stronger in [CV#CV] than in [CVC#CV]. The strength of pi‐gesture also affects spatial articulatory characteristics depending on constriction location and sequential context. [Work supported by NIH.]