Thailand is home to 51 living indigenous languages and 24 living non-indigenous languages,^[1] with the majority of people speaking languages of the Southwestern Tai family, and the national language being Central Thai. Lao is spoken along the borders with the Lao PDR, Karen languages are spoken along the border with Myanmar, Khmer is spoken near Cambodia and Malay is spoken in the south near Malaysia. Sixty-two 'domestic' languages are officially recognized, and international languages spoken in Thailand, primarily by international workers, expatriates and business people, include Burmese, Karen, English, Chinese, Japanese, and Vietnamese, among others.^[2]

This section does not cite any sources. (May 2022)

The sole official language of Thailand is Central Thai (Siamese), a vernacular language in Central (including the Bangkok Metropolitan Region), Southwestern, and Eastern Thailand, along with Thai Chinese ethnic enclaves in outer parts of the country such as Hatyai, Bandon, Nangrong, and Mueang Khonkaen. Central Thai is a Kra-Dai language closely related to Lao, Shan, and numerous indigenous languages of southern China and northern Vietnam. It is the solely language of education (except international schools used English and Chinese school in Maesai used Mandarin) and government and is spoken throughout the country. In practice, almost all Thai nationality are proficient at the level of a native speaker in the Central Thai, despite less than half of the population claiming that they use it as their vernacular language. The standard is written in the Thai alphabet, an abugida that evolved from the Khmer script.

There are several Thai topolects. The Central Thai and Southern Thai is successors of Sukhothai language which divided during 17th century. Northern Thai is spoken in the northern provinces that were formerly part of the independent kingdom of Lan Na, while Isan (a Thai variant of Lao) and Phu Thai are native languages of the northeast. All languages are partially mutually intelligible with Central Thai, with the degree depending on standard sociolinguistic factors. Although all are classified as a separate language by most linguists, the Thai government has historically treated them as dialects of one "Thai language" for political reasons of Thai national identity building. In the 2010 national census, filling in the four Thai languages are not option.

The position of all minority languages, including the largest, i.e. Isan in the Northeast and Kham muang in the North, is precarious given that they are not well supported in Thailand's language education policy.^[14] In the far south, Kelantan-Pattani Malay, also known as Yawi, is the primary community language of the Malay Muslims. Khmer is spoken by older Northern Khmer. Varieties of Chinese are also spoken by the older Thai Chinese population, with the Teochew dialect being best represented. However, the younger Thai Chinese and Northern Khmer trend towards speaking Central Thai. The Peranakan in Southern Thailand speak Southern Thai at home.

Several village sign languages are reported among the mountain peoples ('hill tribes'), though it is not clear whether these are independent languages, as only Ban Khor Sign Language has been described. Two related deaf-community sign languages developed in Chiangmai and Bangkok; the national Thai Sign Language developed from these under the influence of American Sign Language.

The 2014 Ethnologue country report for Thailand, which uses the EGIDS language endangerment assessment scale,^[15] lists one national language (Central Thai), one educational language (Isan), 27 developing languages, 18 vigorous languages, 17 threatened languages, and 7 dying languages.^[16]

Thai is the language of education. The curriculum introduced by the 1999 National Education Act,^[21] which introduced 12 years of free education, emphasized Thai as being the national language. The 2008 Basic Education Core Curriculum^[22] prioritises Thai, although it also mentions 'dialects' and 'local languages', i.e., ethnic minority languages. The monolingual education system is generally seen as ineffective, with one-third of teenagers functionally illiterate.^[23] Illiteracy in Thai is particularly widespread in Thailand's three southernmost provinces as the Patani dialect of Malay is the mother tongue for the majority Malay community. International programs and schools which teach, for example, English or Chinese alongside Thai exist, as do a small number of pilot projects to teach ethnic minority languages alongside Thai in Thai schools.^[14]

• Demographics of Thailand
• Ethnic minorities of Thailand
• Kra-dai languages
• Nationality, religion, and language data for the provinces of Thailand
• Southwestern Tai languages
• Thai language

• Bradley, D. (2007). "East and Southeast Asia". In Moseley, C. (ed.). Encyclopedia of the world’s endangered languages. London: Routledge. pp. 349–424. OCLC 47983733.
• Bradley, D (2007). "Languages of Mainland South-East Asia". In Miyaoka, O.; Sakiyama, O.; Krauss, M. E. (eds.). The vanishing languages of the Pacific Rim. Oxford: Oxford University Press. pp. 301–336.
• "Ethnolinguistic Maps of Thailand" (PDF) (in Thai). Bangkok: Office of the National Culture Commission. 2004.
• Lebar, F. M.; Hickey, G. C.; Musgrave, J. K. (1964). Ethnic groups of mainland Southeast Asia. New Haven: Human Relations Area Files Press. OCLC 409451.
• Luangthongkum, Theraphan (2007). "The Position of Non-Thai Languages in Thailand". In Guan, Lee Hock; Suryadinata, L. (eds.). Language, nation and development in Southeast Asia. Singapore: ISEAS Publishing. pp. 181–194. OCLC 190824881.
• Matisoff, J. A. (1991). "Endangered languages of Mainland Southeast Asia". In Robins, R. H.; Uhlenbeck, E. M. (eds.). Endangered languages. Oxford: Berg Publishers. pp. 189–228. OCLC 464005212.
• Matisoff, J. A.; Baron, S. P.; Lowe, J. B. (1996). Languages and dialects of Tibeto-Burman (PDF). Sino-Tibetan Etymological Dictionary and Thesaurus Monograph Series 1 and 2. Berkeley: University of California Press. ISBN 0-944613-26-8.
• Smalley, W. (1994). Linguistic Diversity and National Unity: Language Ecology in Thailand. Chicago: University of Chicago Press. ISBN 9780226762883. OCLC 29564736.
• Suwilai Premsrirat (2004). "Using GIS For Displaying An Ethnolinguistic Map of Thailand" (PDF). In Burusphat, Somsonge (ed.). Papers from the Eleventh Annual Meeting of the Southeast Asian Linguistics Society. Tempe, Arizona: Arizona State University, Program for Southeast Asian Studies. pp. 599–617.