|Kadai, Daic, Kradai|
|Southern China, Hainan,
Indochina, Northeast India
|Linguistic classification:||Perhaps Austronesian or Austro-Tai|
|ISO 639-2 / 5:||tai|
Distribution of the Kadai language family.
The Tai–Kadai languages, also known as Daic, Kadai, Kradai, or Kra–Dai, are a language family of highly tonal languages found in southern China and Southeast Asia. They include Thai and Lao, the national languages of Thailand and Laos respectively. There are nearly 100 million speakers of these languages in the world. Ethnologue lists 92 languages in this family, with 76 of these languages being in the Kam–Tai branch.
The diversity of the Tai–Kadai languages in southeastern China, especially in Guizhou and Hainan, suggests that this is close to their homeland. The Tai branch moved south into Southeast Asia only about a thousand years ago, founding the nations that later became Thailand and Laos in what had been Austroasiatic territory.
The name "Tai–Kadai" comes from an obsolete bifurcation of the family into two branches, Tai and Kadai (all else). Since this Kadai can only be a valid group if it includes Tai, it is sometimes used to refer to the entire family; on the other hand, some references narrow its usage to the Kra branch of the family.
External relationships 
The Tai–Kadai languages were formerly considered to be part of the Sino-Tibetan family, but outside China they are now classified as an independent family. They contain large numbers of words that are similar in Sino-Tibetan languages. However, these are seldom found in all branches of the family, and do not include basic vocabulary, indicating that they are old loan words.
Several Western scholars have presented suggestive evidence that Tai–Kadai is related to or a branch of the Austronesian language family. There are a number of possible cognates in the core vocabulary. Among proponents, there is yet no agreement as to whether they are a sister group to Austronesian in a family called Austro-Tai, a backmigration from Taiwan to the mainland, or a later migration from the Philippines to Hainan during the Austronesian expansion.
The Austric proposal suggests a link between Austronesian and the Austroasiatic languages. Echoing part of Benedict's conception of Austric, who added Tai–Kadai and Hmong–Mien to the proposal, Kosaka (2002) argued specifically for a Miao–Dai family.
In China, they are called Zhuang–Dong languages and are generally considered to be related to Sino-Tibetan languages along with the Miao–Yao languages. It is still a matter of discussion among Chinese scholars whether Kra languages such as Gelao, Qabiao, and Lachi can be included in Zhuang–Dong, since they lack the Sino-Tibetan similarities that are used to include other Zhuang–Dong languages in Sino-Tibetan.
Internal classification 
Tai–Kadai consists of five well established branches, Hlai, Kra, Kam–Sui, Tai, and the Ong Be (Bê) language:
- Ong Be (Hainan; Lin'gao (临高) in Chinese)
- Kra (called Kadai in Ethnologue and Gēyāng (仡央) in Chinese)
- Kam–Sui (mainland China; Dong–Shui (侗水) in Chinese)
- Hlai (Hainan; Li (黎) in Chinese)
- Tai (southern China and Southeast Asia)
Based on the large amount of vocabulary they share, the Kam–Sui, Be, and Tai branches are often classified together. (See Kam–Tai.) However, Weera Ostapirat believes this is negative evidence, possibly due to lexical replacement in the other branches. He also claims that morphological similarities suggest instead that Kra and Kam–Sui be grouped together as Northern Kadai on the one hand, and Hlai with Tai as Southern Kadai on the other. The position of Ong Be in Ostapirat's proposal is undetermined.
This classification is used by Ethnologue, though by 2009 Lakkja was made a third branch of Kam–Tai and Biao was moved into Kam–Sui.
- Diller, Anthony, Jerry Edmondson, Yongxian Luo. (2008). The Tai–Kadai Languages. London [etc.]: Routledge. ISBN 978-0-7007-1457-5
- Ethnologue Tai–Kadai family tree
- Ostapirat, W. (2005). "Kra–Dai and Austronesian: Notes on phonological correspondences and vocabulary distribution", pp. 107–131 in Sagart, Laurent, Blench, Roger & Sanchez-Mazas, Alicia (eds.), The Peopling of East Asia: Putting Together Archaeology, Linguistics and Genetics. London/New York: Routledge-Curzon.
- Kosaka, Ryuichi. 2002. "On the affiliation of Miao-Yao and Kadai: Can we posit the Miao-Dai family." Mon-Khmer Studies 32:71-100.
- Norquest, Peter K. 2007. A Phonological Reconstruction of Proto-Hlai. Ph.D. dissertation, Department of Anthropology, University of Arizona.
- Edmondson, Jerold A. and David B. Solnit, editors. 1988. Comparative Kadai: Linguistic studies beyond Tai. Summer Institute of Linguistics and the University of Texas at Arlington Publications in Linguistics, 86. Dallas: Summer Institute of Linguistics and the University of Texas at Arlington. vii, 374 p.
- Edmondson, Jerold A. and David B. Solnit, editors. 1997. Comparative Kadai: the Tai branch. 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. vi, 382 p.
- Edmondson, J.A. and D.B. Solnit eds. 1997. Comparative Kadai: the Tai branch. Dallas: Summer Institute of Linguistics and the University of Texas at Arlington. ISBN 0-88312-066-6
- Blench, Roger. 2004. Stratification in the peopling of China: how far does the linguistic evidence match genetics and archaeology? Paper for the Symposium "Human migrations in continental East Asia and Taiwan: genetic, linguistic and archaeological evidence". Geneva June 10–13, 2004. Université de Genève.
- Sagart, Laurent. 2004. The higher phylogeny of Austronesian and the position of Tai–Kadai. Oceanic Linguistics 43. 411–440.
Further reading 
- Diller, A., J. Edmondson, & Yongxian Luo, ed., (2005). The Tai–Kadai languages. London [etc.]: Routledge. ISBN 0-7007-1457-X
- Edmondson, J. A. (1986). Kam tone splits and the variation of breathiness.
- Edmondson, J. A., & Solnit, D. B. (1988). Comparative Kadai: linguistic studies beyond Tai. Summer Institute of Linguistics publications in linguistics, no. 86. [Arlington, Tex.]: Summer Institute of Linguistics. ISBN 0-88312-066-6
- Ostapirat, W. (2000). Proto-Kra. Linguistics of the Tibeto-Burman Area, 23 (1), 1–251.
- Somsonge Burusphat, & Sinnott, M. (1998). Kam–Tai oral literatures: collaborative research project between. Salaya Nakhon Pathom, Thailand: Institute of Language and Culture for Rural Development, Mahidol University. ISBN 974-661-450-9
- Tai–Kadai Languages. (2007). Curzon Pr. ISBN 978-0-7007-1457-5
- Tai–Kadai language page from the MultiTree Project at the LINGUIST List
- Word lists of Tai–Kadai languages from the Austronesian Basic Vocabulary Database
- StarLing: Tai–Kadai 100-word lists and etymology
- Comparative Tai–Kadai Swadesh vocabulary lists (from Wiktionary's Swadesh list appendix)