The Tai-Kadai languages form one of the world’s major language families, as they are spoken by close to 100 million speakers (Diller et al. 2008). The language family extends over a vast linguistic area covering much of mainland Southeast Asia. Within China, Tai-Kadai speakers occupy an area adjacent to Southeast Asia extending eastwards to Hǎinán Island and Guǎngdōng Province and westwards to Déhóng 德宏 prefecture in Yúnnán province on the China-Burma border, northwards to Guìzhōu and the Yúnnán-Sìchuān border, and so…