One of the more annoying nomenclature problems in the world of language is that of the Tai (sometimes called “Thai”) language family, whose most prominent member is Thai (sometimes called “Tai”). The two English words are both from the self-designation of T(h)ai-speakers; the orthographic distinction is basically a convenient device to differentiate language and family, although it also reflects the fact that the name is pronounced in some languages with an aspirated t and in some with an unaspirated one.
But even if we have the family name straight, what are the main languages included in the Tai family? George L. Campbell’s Concise Compendium of the World’s Languages gives a nice, compact answer: “[Thai] is the most important member of the Tai family which also includes Lao, Shan, and Yuan.” I nodded my head at Lao and Shan and shook it in bewilderment when I hit Yuan. I knew of no such language. I went to Andrew Dalby’s Dictionary of Languages and found:
The South-western division includes the two best known, Thai or Siamese, spoken in central Thailand, and Lao of Laos and north-eastern Thailand. A continuum of dialects in areas to the north of these begins with Ahom, an extinct language of the Indian state of Assam, and Shan; it continues eastwards with Lanna Thai and ends with the minority languages of Laos and Vietnam usually known as Black Tai, Red Tai and White Tai.
(I pause for the inevitable black-tie jokes.) No help here. So I went to the “Tai Languages” chapter of The World’s Major Languages and read the more detailed description there:
Southwestern, including Ahom (extinct), Khamti, Tai Nuea (Chinese Shan, Dehong Dai), Tai Long (Shan), Khuen, Tai Lue (Xishuangbanna Dai), Kam Muang (Tai Yuan, Northern Thai), Thai (Siamese, Central Thai), Southern Thai, Lao (Lao dialects in Thailand are also called “Northeastern Thai”), White Tai, Tai Dam (Black Tai), Red Tai and several other languages…
At first my eyes glazed over, then I buckled down and focused—and I saw it: Tai Yuan, a parenthetical variant of “Kam Muang.” I’d never heard of the latter, but the other parenthetical variant, “Northern Thai,” was familiar to me; Dalby had an entry on it under the rubric “Lanna Thai, Khün and Lü.” And sure enough, The entry begins “The Lanna or Tai Yuan language of northern Thailand…” So we have our Top Four: Thai, spoken by about 25 million people; Lao, spoken by 15 million; Lanna/Yuan/Northern Thai, spoken by 6,500,000; and Shan, spoken by 3 million. (The Northern Tai [n.b.] language Zhuang may be spoken by over 10 million people in southern China, but it’s hard to tell because the Zhuang people, in Dalby’s words, “have not, historically, been anxious to project a distinct ethnic identity. They wanted to be Chinese—and Chinese they have largely become.”)
If you’d like to see where these languages are located, there’s a map about halfway down this page; unfortunately, although a number of minor languages are shown, neither Northern/Lanna Thai nor Southern Thai (spoken near the Malaysian border) is there. Such are the perils of investigating one of the least studied of the major language families.