The Central Tai languages include southern dialects of Zhuang, and various Nung and Tày dialects of northern Vietnam.

Southwestern Tai also displays this kind of aspiration contrast.

Certain languages in predominantly Central Tai-speaking areas, such as Caolan and Nùng An[1] in northern Vietnam, display Northern Tai features as well.

Jerold A. Edmondson calls Caolan a "tertium quid".

[2] Jerold Edmondson's (2013)[3] computational phylogenetic analysis of the Tai languages shows Tay and Nung to be coherent branches under Central Tai.