Which Tai dialects belong to the Central Tai group?

The Central Tai group consists of the Tay dialects spoken in northern Vietnam, as well as various dialects spoken in Guangxi, China, such as Longzhou.1

These dialects are distinguished from other Tai groups by specific phonological and lexical features. For example, in the treatment of certain Proto-Tai consonant clusters, such as tr- and thr-, the Central dialects have merged these into a single sound, whereas they remain distinct in other groups. Additionally, vocabulary evidence—such as the shared term for "sky" between Central and Southwestern dialects, or the shared term for "beard" between Central and Northern dialects—helps define the boundaries of this group.23