Editing Tai languages (section)

===Haudricourt (1956)===
[[André-Georges Haudricourt|Haudricourt]] emphasizes the specificity of Dioi (Zhuang) and proposes to make a two-way distinction between the following two sets.<ref>Haudricourt, André-Georges. 1956. De la restitution des initiales dans les langues monosyllabiques : le problème du thai commun. Bulletin de la Société de Linguistique de Paris 52. 307–322.</ref> The original language names used in Haudricourt's (1956) are provided first; alternative names are given in parentheses.

{{tree list}}
* '''Tai'''
** Dioi group: [[Yei Zhuang language|Yei Zhuang]], [[Yongbei Zhuang]], [[Youjiang Zhuang]], [[Bouyei language|Bouyei]] (Buyi)
** Tai proper: [[Ahom language|Ahom]], [[Shan language|Shan]], [[Thai language|Siamese]] (Thai), [[Lao language|Lao]], [[Tai Dón language|White Tai]] (Tai Dón), [[Tai Dam language|Black Tai]] (Tai Dam), [[Zhuang languages#Southern Zhuang|Southern Zhuang]], [[Tày language|Tho]] (Tày), [[Nung language (Tai)|Nung]]
{{tree list/end}}

Characteristics of the Dioi group pointed out by Haudricourt are
* r- corresponding to the lateral l- in the other Tai languages,{{verify source|date=August 2021}}<!-- Appears to contradict Li and Pittayaporn. -->
* divergent vowel system characteristics, e.g. 'tail' has an /a/ vowel in Tai proper, as against /ə̄/ in Bo-ai, /iə/ in Tianzhou, and /ɯə/ in Tianzhou and Wuming, and
* the lack of aspirated stops and affricates, which are found everywhere in Tai proper.