The Newsletter 77 Summer 2017

The Tai-Kadai languages and their genetic affiliation

Yongxian Luo

Tai-Kadai is a family of diverse languages found in southern China, northeast India and much of Southeast Asia, with a diaspora in North America and Europe. It is one of the major language families in East and Southeast Asia. The number of the Tai-Kadai languages is estimated to be close to one hundred, with approximately 100 million speakers who are spread across six countries: China, Thailand, Laos, Myanmar, India and Vietnam. Tai-Kadai is a well-established family in its own right. However, its genetic affiliation remains open.

As the name itself suggests, Tai-Kadai is made up of two major groups: Tai and Kadai. Tai, also known as Kam-Tai, comprises the best known members of the family: Thai and Lao, the national languages of Thailand and Laos, whose speakers alone account for over half of the Tai-Kadai population. Thai and Lao are closely related to Zhuang, the language of the largest minority group in China. Other important members within the Tai group include Kam and Sui, with several million speakers.

Kadai refers to a number of lesser-known languages, some of which have only a few hundred fluent speakers or even less.1 Diller, A. et al. (eds.) 2008. The Tai-Kadai Languages. London and New York: Routledge; Luo, Y. 2017. ‘Tai-Kadai languages in China’, Encyclopedia of Chinese Language and Linguistics 4:249-257.  The majority of Tai-Kadai languages have no writing systems of their own, particularly Kadai languages. Those with writing systems include Thai, Lao, Sipsongpanna Dai and Tai Nua. These use the Indic-based scripts. Others use Chinese character-based scripts, such as the Zhuang and Kam-Sui in southern China and surrounding regions. Romanized scripts were also introduced in the 1950s by the Chinese government for the Zhuang and the Kam-Sui languages. Almost each group within Tai-Kadai has a rich oral history tradition. 

In the early days of Sino-Tibetan studies, Tai was assumed to be a member of the Sino-Tibetan family. This theory was challenged by Paul Benedict, who put forward the hypothesis of a Tai-Austronesian alliance.2 Benedict, P.K. 1942. ‘Thai, Kadai and Indonesian: a new alignment in southeast Asia’, American Anthropologist 44:576-601; Benedict, P.K. 1975. Austro-Thai language and culture, with a glossary of roots. New Haven: HRAF Press.  Benedict’s position has gained increasing acceptance among Western scholars. Benedict made the links between Kam-Tai and a number of lesser known languages such as Gelao, Lachi and Laqua, for which the term Kadai was coined. More recently, terms like Kra and Kra-dai have been proposed for these latter languages.

While there is no question about the status of Tai as a distinct language family, the genetic affiliation of Tai-Kadai remains controversial. Opinions are divided into three camps: (1) Sino-Tai; (2) Austro-Tai; (3) Sino-Tibetan-Austronesian. The Sino-Tai hypothesis assumes the membership of Tai under Sino-Tibetan while the Austro-Tai theory argues for a genetic relationship between Tai and Austronesian. The Sino-Tibetan-Austronesian hypothesis proposes a super phylum that includes Chinese, Tai-Kadai, Miao-Yao, and Austronesian. 

Today western researchers generally embrace the Austro-Tai theory while the majority of Chinese scholars still uphold the traditional hypothesis for a Sino-Tai alliance. A number of Chinese scholars, however, are siding with Benedict in linking Tai-Kadai with Austronesian, excluding Tai-Kadai from Sino-Tibetan.3 Wang, W.S-Y. 2015. ‘The Peoples and Languages of China’, Chapter 1 of The Oxford Handbook of Chinese Linguistics, ed. by William S-Y Wang and Chaofen Sun. Oxford University Press.  The advancement in the phylogenetic study of Kam-Tai and Austronesian peoples, along with several anthropological traits such as face-tattooing and teeth-blackening, lend support to this view.

On the basis of comparison between Kam-Tai and Austronesian, Deng and Wang believe that Kam-Tai and Austronesian are genetically related.4 Deng, X. & W.S-Y Wang. 2009. Zhōngguó de yǔyán jí fāngyán de fēnlèi [Classification of Languages and Dialects of China . Běijīng: Zhōnghuá Shūjú.] Their conclusion is arrived at through solid evidence: some 40 basic vocabulary items in Swadesh’s list are found to be shared by Kam-Tai and Austronesian. These include several items from Yakhontov’s list — a 35-word subset of the Swadesh list posited as especially stable by Russian linguist Sergei Yakhontov for calculating the genetic relationships between languages. However, not all Austronesianists are convinced; for them, the evidence cited proof is in fact far from consistent, and should be considered as result of contact rather than genetic link.

On the other hand, recent research provides evidence from Kam-Tai and Chinese showing that the two languages share basic vocabulary and morphological processes.5 Luo, Y. 2012. ‘Some Sino-Tai Word Families’, paper presented to the International Conference on Sino-Tibetan Languages and Linguistics, Nanyang University of Technology, Singapore; Luo, Y. 2013. ‘Stable roots in Kam-Tai’, pp.468-485 in Festschrift volume for Professor William S-Y Wang on the Occasion of his 80th Birthday, eds. Shi Feng and Peng Gang, Hong Kong: City University of Hong Kong Press.  Little parallel development can be observed between Kam-Tai and Austronesian in this regard. This is at variance with Benedict’s claims that Tai and Chinese share little in basic vocabulary and morphology. Since basic vocabulary and morphology is relatively stable and resistant to borrowing, this finding is worth considering.

For now, evidence from both sides is contested. The Sino-Tai hypothesis needs to be revisited, as does the Austro-Tai hypothesis. Since Kadai languages may hold a key to the genetic position of Tai-Kadai, good descriptive and comparative work needs to be done to unveil key aspects of historical connection.6 Holm, D. 2013. Mapping the Old Zhuang Character Script: A Vernacular Writing System from Southern China. Brill.  The issue of genetic affiliation of Tai-Kadai remains a fascinating topic of academic pursuit.

Yongxian Luo, Associate Professor, Asia Institute, The University of Melbourne(