The Tai family in one paragraph
Thai belongs to the Tai branch of the Kra-Dai (or Tai-Kadai) family, a group of tonal languages spread from southern China to northeast India. Within Tai, Thai sits in the southwestern group with Lao, Shan in Myanmar, Tai Lue and the Tai languages of northern Vietnam, and further out it is related to Zhuang in southern China, which has more than ten million speakers of its own. These languages share a common stock of basic words (numbers, body parts, everyday verbs), a similar grammar, and tones that grew out of the same historical sound changes, which is why the Thai consonant classes have close equivalents in Lao writing.
The main languages
| Language | Where | Family | First-language speakers | Written in |
|---|---|---|---|---|
| Central Thai ภาษาไทยกลาง | Central plains and Bangkok; the national standard everywhere | Tai (Kra-Dai) | about 20 million | Thai script |
| Isan ภาษาอีสาน | Northeast (Isan) | Tai (Kra-Dai), a variety of Lao | about 15 million | Thai script today; Tai Noi and Tai Tham in the past |
| Northern Thai (Kam Mueang) คำเมือง | North: Chiang Mai, Chiang Rai, Lampang and the old Lanna region | Tai (Kra-Dai) | about 6 million | Thai script; the Tai Tham (Lanna) script in temples and revival |
| Southern Thai (Pak Tai) ภาษาปักษ์ใต้ | The southern peninsula | Tai (Kra-Dai) | about 4.5 million | Thai script |
| Northern Khmer ภาษาเขมรถิ่นไทย | Surin, Buriram, Sisaket | Austroasiatic | about 1.4 million | Thai script, informally |
| Pattani Malay ภาษามลายูปัตตานี | Pattani, Yala, Narathiwat | Austronesian | about 1 million | Jawi (Arabic-based); also Thai script and Latin letters |
The speaker numbers are rough estimates of first-language speakers, after Ethnologue; other sources differ widely, partly because Thai censuses have not recorded the regional Tai languages separately. Ethnologue counts more than seventy living languages in Thailand in all.
Central Thai
The language of the central plains, standardised on the speech of Bangkok and taught in every school. Most Thais speak it, many as a second language alongside a regional one at home. It is the Thai of government, the media and this site, and the language the Thai script was shaped around.
Isan
The language of the northeast, the largest region of the country, is a variety of Lao, and on the ground it is the second language of Thailand by number of speakers. It was once written in the Tai Noi script, close to modern Lao writing, and in Tai Tham for religious texts; today it is written, when it is written at all, in Thai letters. Isan is heard everywhere in Bangkok, through migration, and in luk thung and mor lam music.
Northern Thai (Kam Mueang)
The language of the old kingdom of Lanna, centred on Chiang Mai. It has its own tones and much of its own vocabulary, and its own script, Tai Tham (also called the Lanna script), which survives in temples, in manuscripts and in a modern revival on signs and in schools. Speakers call it คำเมือง, kham mueang, “the speech of the mueang”, the old city-states of the north.
Southern Thai (Pak Tai)
Spoken from Chumphon down to the Malaysian border by Thai speakers of the south. It is close to Central Thai in grammar and vocabulary but famously quick, with shortened words and a tone system of its own, and Central Thai listeners often find it hard to follow at speed. It is written in Thai script.
Pattani Malay
The everyday language of the Malay Muslim majority in Pattani, Yala and Narathiwat, and part of Songkhla. It is an Austronesian language, related to the Malay of Kelantan across the border rather than to Thai, and it has no tones. Locally it is often called Yawi, after Jawi, the Arabic-based script traditionally used to write it.
Northern Khmer
A variety of Khmer spoken in the lower northeast, especially in Surin, Buriram and Sisaket, by people whose families have lived there for centuries. It belongs to the Austroasiatic family with Cambodian Khmer and Mon. Younger speakers increasingly shift to Thai or Isan, and the language is written, informally, in Thai letters.
Other languages
Around these sit many smaller languages: other Tai languages such as Phu Thai, Nyaw and Shan; Mon and Kuy, which, like Khmer, are Austroasiatic; the Karen languages along the Myanmar border; Hmong, Mien, Akha, Lahu and Lisu in the northern hills; Moken and Urak Lawoi on the Andaman coast; and the Chinese varieties of the large Thai Chinese community, Teochew above all. Several of the smaller ones are endangered, as younger speakers move to Thai.
Status and scripts
Thai law and education have long treated the regional Tai languages as dialects of Thai, and Central Thai as the only standard. Linguists generally count Northern Thai, Isan and Southern Thai as languages in their own right, separate from Central Thai though closely related. In practice the line is a matter of politics and identity as much as of grammar.
The Thai script is used for almost all of them. Its letters were built for Central Thai, so writing another Tai language in it means bending the consonant classes and tone marks to a different tone system, and spellings vary from writer to writer. That is one reason the older scripts, Tai Tham above all, matter to the people who keep them alive.