Proto-Southwestern Tai revised

Southwestern Tai (SWT) is the best studied among the three main branches of the Tai language family according to Li (1960)’s classification. Because discrepancies among earlier proposals (Brown 1985; Jonsson 1991; Li 1977; and Sarawit 1973) are major obstacles both in subgrouping SWT varieties and in reconstructing PT, this paper makes use of data from 28 varieties incorporating new data from lesser-known languages including the author’s own fieldwork, to propose a revised PSWT reconstruction. It first reviews the earlier proposals and then puts forward a new reconstruction of PSWT which makes the following claims: 1) there was a distinct series of uvular consonants in PSWT, 2) there is no evidence for clusters *pʰr/l-,*kʰl-, and *mr- at the PSWT level, 3) mid back unrounded vowel *ɤ must be reconstructed for PSWT, and 4) vowel length was contrastive. Last but not least, it discusses important features of the proposed PSWT phonology that have implications for the reconstruction of Proto-Tai, including 1) redundancy of length contrast among non-high vowels, 2) gaps within the sub-system initial clusters, and 3) the defective nature of the vowel *ɤ.