The Articulatory TBU: Gestural Coordination of Lexical Tone in Thai

Recent literature in Articulatory Phonology (AP) has promoted the idea that tone is an articulatory gesture, similar to those that make up consonants and vowels (Prieto and Torreira 2007, Gao 2008). When treated as gestures, tones should be co-selected and coordinated like other articulatory gestures. The co-selection of T(one) gestures with C(onsonant) and V(owel) gestures is reminiscent of the autosegmental “association” of tone with tone-bearing unit (TBUs); however, work with tone in the framework of AP has not formalized the articulatory conceptualization of the TBU. In this paper, I argue that a TBU is an articulatory gesture that T gestures can coordinate with. I also argue that moras correspond to groups of coordinated articulatory gestures, and that these mora-sized sets of gestures are coordinated with each other. In some languages, tone is coordinated within the group of articulatory gestures. I present evidence from an articulatory and acoustic study on Thai, a tonal language that uses the mora as its TBU. The rest of the paper is organized as follows: in Section 2, I provide the theoretical background for this study, as well as the hypotheses and predictions under the current framework. In Section 3, I describe the methodology used to collect data. In Section 4, I present the data from the study. In Section 5, I discuss the data and its implications for the treatment of tone in AP.