The internal classification of the Southwestern Tai dialects is still not well agreed on.
Chamberlain (1975)
Chamberlain (1975) divides Southwestern Tai into 4 branches.[1]
Chamberlain based his classification on the following phonological patterns. (Note: For an explanation of the notation system for Tai tones, see
Proto-Tai language#Tones.)
/p/ vs. /ph/
tone *A column split/merger pattern
tone *BCD columns split/merger patterns
B-DL tonal coalescence
Proto-Southwestern Tai
Branch with distinguishing innovation: /p/
Branch with distinguishing innovation: *A 1-23-4
Tse Fang, a variety of
Tai Nuea spoken at Zhefang (遮放镇) in
Mangshi, Yunnan, China
Tai Mao, a variety of
Tai Nuea spoken at
Nam Hkam, Shan State, Myanmar
Muang Ka, a variety of
Tai Nuea spoken at Muang Ka in Muang Baw, Yunnan, China
Branch with distinguishing innovation: *ABCD 123-4; B=DL
Edmondson & Solnit (1997) divide the Southwestern Tai dialects into two major subgroups. According to this classification, Dehong Tai and Khamti are the first languages to have split off from the Southwestern Tai branch.[4]
Northern:
Tai Nua = Shan-Tayok (Chinese Shan),
Khamti
Southern: Burman
Shan ("Shan proper"), all other Southwestern Tai
A transition zone between the Northern and Southern groups occurs among the Tai languages (including Tai Mau) around the Burma-China border region of Mangshi, Namhkam, and Mu-se near
Ruili.
This bipartite division of Southwestern Tai is argued for by Edward Robinson in his paper "Features of Proto-Nüa-Khamti" (1994). The following features set off the Nüa-Khamti group from all the other Southwestern Tai dialects.
The low vowels /ɛ/ and /ɔ/ have merged with /e/ and /o/, respectively.
*ʔb > m
Luo (2001)
Luo Yongxian (2001) also recognizes the uniqueness of Dehong Tai (Tai Nuea), but argues for that it should be placed in a separate Northwestern Tai branch with Southwestern Tai as a sister branch.[5] Luo claims that the Northwestern Tai branch has many Northern Tai and Central Tai features that are not found in Southwestern Tai. His proposed tree for the Tai branch is as follows.
According to Pittayaporn (2009:301), Southwestern Tai (his subgroup Q) is defined by a phonological shift of *kr- → *ʰr-.[6]
Pittayaporn (2014) also suggests that Southwestern Tai began to disperse southward after the 7th century C.E. but before the 11th century C.E. (between 700 and 1000 C.E., during the late
Tang dynasty or early
Song dynasty), as evidenced by loanwords from Late
Middle Chinese.[7]
Pittayaporn (2018)[8] recognizes two branches within Southwestern Tai, namely Eastern and Western. The Eastern branch consists of the closely related languages
Black Tai,
White Tai, and
Red Tai, while the Western branch is much more internally diverse. The Western branch also contains a Southern group consisting of
Thai and
Lao.
Southern sub-branch:
Thai,
Lao, etc. (defining innovations: *ɓl- > ɗ- and *ʰr > h-)
Pittayaporn, et al. (2018)[9] note that following sound changes from Proto-Southwestern Tai (PSWT) to the Tai varieties represented in the
Sukhothai and
Ayutthaya inscriptions, and conclude that the Sukhothai and Ayutthaya inscriptions in fact represent the same language.
the merger of dorsal obstruents
the merger of PSWT *aɯ and *aj
the merger of PSWT *ɲ-, *j- and *ʔj-
the loss of voicing distinction in sonorants
*ɓl- > d-
*kʰr- > kʰ-
*ʰr- > h-
Dialects
Southern Thai (Pak Thai) is often posited to be the most divergent; it seems to retain regular reflexes of early tonal developments that were obscured in the other (Central–Eastern) languages. The reconstructed language is called Proto-Thai; cf.
Proto-Tai, which is the ancestor of all of the
Tai languages.
According to Ethnologue, other Southwestern dialects are
Tai Ya (China),
Pu Ko (Laos),
Pa Di (China),
Tai Thanh (Vietnam),
Tai Long (Laos),
Tai Hongjin (China),
Yong (Thailand). It is not clear where they belong in the classification above. Ethnologue also lists under Tai, without further classification,
Kuan (Laos),
Tai Do (Viet Nam),
Tai Pao (Laos), and
Tay Khang (Laos). Geographically these would all appear to be Southwestern.[11]
Ethnologue also includes
Tày Sa Pa (Sapa) of Vietnam, which Pittayaporn excludes from Southwestern Tai but classifies as the most closely related language outside of that group. Pittayaporn also includes
Yoy, which Ethnologue classifies as a
Northern Tai language.[11]
^Chamberlain, James R. 1975. "
A new look at the history and classification of the Tai dialects." In J. G. Harris and J. R. Chamberlain, eds, Studies in Tai Linguistics in Honor of William J. Gedney, pp. 49–60. Bangkok: Central Institute of English Language, Office of State Universities.
^Chamberlain, James R. 1984. "The Tai dialects of Khammouan province: their diversity and origins". Science of language, 4:62–95.
^Edmondson, Jerold A., Solnit, David B., authors. 1997. "Comparative Shan." In Comparative Kadai: The Tai branch, Jerold A. Edmondson and David B. Solnit (eds.). pages 337–359. Summer Institute of Linguistics and the University of Texas at Arlington Publications in Linguistics 124. Dallas: Summer Institute of Linguistics and the University of Texas at Arlington.
^Pittayaporn, Pittayawat (2018). Subgroup structure of Southwestern Tai based on early phonological innovations. Paper presented at the 28th Annual Meeting of the Southeast Asian Linguistics Society, held May 17–19, 2018 in Kaohsiung, Taiwan.
^Pittayawat Pittayaporn, Sireemas Maspong, Shinnakrit Tangsiriwattanakul, and Yanyong Sikkharit (2018). The genetic relationship between Sukhothai and Ayutthaya. Paper presented at the 28th Annual Meeting of the Southeast Asian Linguistics Society, held May 17–19, 2018 in Kaohsiung, Taiwan.