Tonal Developments and Southwestern Tai Subgrouping

This article evaluates the use of tonal development as criteria for Southwestern Tai subgrouping. A literature review shows that Brown (1965) and Chamberlain (1975), the two most influential proposals, both use tonal splits and mergers as main criteria. However, this approach is not consistent with the shared-innovation method used in subgrouping, because many tonalchanges may not in fact be shared innovations and because most tonal changes are relatively late developments. Therefore, a subgrouping proposal for Southwestern Tai should primarily use as criteria consonantal and vocalic changes that can be shown empirically to have occurred relatively early.