The Online Encyclopedia and Dictionary






Thai language

The Thai language is the official language of Thailand. The Thai name for the language is ภาษาไทย (phasa thai, meaning "the language of Thais"). Thai is part of the Tai languages group of the Tai-Kadai language family. The Tai-Kadai languages are thought to have originated in southern China, and some linguists have proposed links to the Austroasiatic, Austronesian, or Sino-Tibetan language families. It is a tonal and analytic language. The combination of tonality, complex orthography, relational marker s and a different phonology can make Thai a difficult language for Westerners to learn.

Thai (ภาษาไทย [phasa thai])
Spoken in: Thailand
Region: --
Total speakers: 46–50 million
Ranking: 24
Genetic classification: Tai-Kadai

      East Central
       Chiang Saeng

Official status
Official language of: Thailand
Regulated by: --
Language codes
ISO 639-1 th
ISO 639-2 tha


Languages and Dialects

Standard Thai, also known as Central Thai or Siamese, is the official language of Thailand, spoken by about 25 million people (1990) including speakers of Bangkok Thai (although the latter is sometimes considered as a separate dialect). Khorat Thai is spoken by about 400,000 (1984) in Nakhon Ratchasima; it occupies a linguistic position somewhere between Central Thai and Isan, and may be considered a dialect of either.

In addition to Standard Thai, Thailand is home to several other related Tai languages, including:

  • Isan (Northeastern Thai), the language of the Isan region of Thailand, is considered by some to be a dialect of the Lao language, which it closely resembles. It is spoken by about 15 million people (1983).
  • Lü (Tai Lue, Dai), spoken by about 78,000 (1993) in northern Thailand.
  • Northern Thai (Lanna, Kam Mueang, or Tai Yuan), spoken by about 6 million (1983).
  • Phuan , spoken by an unknown number of people in central Thailand and Isan.
  • Phu Thai , spoken by about 156,000 around Nakhon Phanom province (1993).
  • Shan (Thai Luang, Tai Long), spoken by about 56,000 in north-west Thailand (1993).
  • Song , spoken by about 20,000 to 30,000 in central and northern Thailand(1982).
  • Southern Thai (Pak Dtai or Dambro), spoken about 5 million (1990).
  • Tai Dam , spoken by about 20,000 (1991) in Isan and Saraburi province.

Statistics are from Ethnologue 2003-10-4 . Many of these languages are spoken by larger numbers outside Thailand. Most speakers of dialects and minority languages speak Central Thai in addition.

Within Standard Thai, there are different forms for different social contexts:

  • Street Thai: informal, without polite terms of address, as used between close relatives and friends.
  • Elegant Thai: official and written version, includes respectful terms of address; used in simplified form in newspapers.
  • Rhetorical Thai: used for public speaking.
  • Sacred Thai.
  • Royal Thai.

Less educated Thais can speak only at the first level. Few can speak the Sacred or Royal versions.


Main article: Thai alphabet

The Thai alphabet probably derives from the Old Khmer (อักขระเขมร) script, which is a southern Brahmic script of the Indic family. Notable features include:

  1. It is an abugida script, in which the implicit vowel is a short open a for consonants standing alone and a short open o if the initial consonant is followed by another consonant.
  2. Tone markers are placed above the initial consonant of a syllable or on the last consonant of an initial consonant cluster.
  3. Vowels associated with consonants are nonsequential: they can be located before, after, above or below their associated consonant, or in a combination of these positions.

The latter in particular causes problems for computer encoding and text rendering.

There is no universal standard for transliterating Thai into English. For example, the name of King Rama IX, the present monarch, is transliterated variously as Bhumibol, Phumiphon, or many other versions. Guide books, text books and dictionaries may each follow different systems. For this reason, most language courses recommend that learners master the Thai alphabet. In scholarly usage, French scholars tend to romanize Thai with a letter-for-letter transcription according to the original Sanskrit value of the characters. Anglophone scholars generally prefer either a simplified phonetic rendering or some variation on the International Phonetic Alphabet. This article uses a simplified IPA system which does not indicate tone or vowel quantity.

The Thai Royal Institute [1] publishes sets of rules for transliterating Thai words into the Roman alphabet and vice versa (the Royal Thai General System of Transcription), but these are far from universally applied. In 1998, the Royal Institute forwarded guidlines for transliteration to the International Organization for Standardization (ISO)[2] (ISO 11940:1998)


From the perspective of linguistic typology, Thai can be considered to be an analytic language. The word order is Subject-Verb-Object, although the subject is often omitted. As in many Asian languages, the Thai pronominal system varies according to the sex and relative status of speaker and audience.


Adjectives follow the noun. A duplicated adjective is used to identify a person, e.g. คนอ้วนๆ (khon uan uan)- "The fat person."

Comparatives take the form "A X กว่า (gwa) B" (A is more X than B). The superlative is expressed as A X ที่สุด (theesut).


Verbs do not inflect (i.e. do not change with person, tense, voice, mood or number) nor are there any participles. Duplication conveys the idea of doing the verb a lot. The passive voice is indicated by the insertion of โดน (dohn) or ถูก (thuuk) before the verb. Tense is conveyed by tense marker s before or after the verb: กำลัง (gamlang) before the verb or อยู่ (yuu) after the verb for the present; จะ (ja) before the verb for the future; ได้ (dai) before the verb (or a time expression) for the past.


Many adverbs are expressed by a duplicated adjective. Adverbs usually follow the verb.


Nouns are uninflected and have no gender; there are no plural forms or articles. Plurals are expressed by adding "nouns of multitude" (ลักษณนาม) or classifiers in the form of noun-number-classifier, e.g. "teacher five person" for "five teachers".

While in English, such classifiers are usually absent ("four chairs") or optional ("two bottles of beer" or "two beers"), a classifier is almost always used in Thai (hence "chair four item" and "beer two bottle").


Subject pronouns are often omitted, while nicknames are often used where English would use a pronoun. There are specialised pronouns in the royal and sacred Thai languages. The following are appropriate for conversational use:

  • ผม (phom) = I/me (masculine)
  • ดิฉัน (di-chan) = I/me (feminine)
  • ฉัน (chan) = I/me (masculine or feminine; informal)
  • คุณ (khun) = you (polite)
  • เธอ (thœ) = you (informal)
  • เรา (rao) = we
  • เขา (khao) = he/she
  • มัน (man) = it
  • พวกเขา (phuak-khao) = they
  • พี่ (phee) = older brother or sister (often used loosely for older non-relatives)
  • น้อง (nong) = younger brother or sister (often used loosely for younger non-relatives)


The particles are often untranslatable words added to the end of a sentence to indicate respect, a request, encouragement or other moods (similar to the use of intonation in English), as well as varying the level of formality. They are not used in written Thai. The most common particles indicating respect are ครับ (pronounced "khrap", with a high tone, the "r" sound is usually omitted) for a man, and ค่ะ (pronounced "kha" with a falling tone) for a woman; these can also be used to indicate an affirmative.

Other common particles are:

  • จ๊ะ (ja) indicating a request;
  • จ้ะ, จ้า or จ๋า (ja) indicating emphasis;
  • ละ or ล่ะ (la) indicating emphasis;
  • สิ (si) indicating emphasis or an imperative; and
  • นะ (na) indicating a request.



There are five phonemic tones: middle, low, high, rising and falling. They are indicated in the written script by a combination of the class of the initial consonant (high, mid or low), vowel length (long or short), closing consonant (unvoiced/stop or voiced/sonorant) and sometimes one of four tone mark s. The tonal rules are shown in the following chart:

Thai Tones Long vowel, or vowel plus voiced consonant Long vowel plus unvoiced consonant Short vowel, or short vowel plus unvoiced consonant Mai ek (อ่) Mai tho (อ้)
High class consonant rising low low low falling
Mid class consonant mid low low low falling
Low class consonant mid falling high falling high

There are a further two, relatively rare tone marks: mai tri (อ๊) and mai chattawa (อ๋); these always indicate a high and a rising tone respectively.

The letters ห (high class) and อ (mid class) are often used as silent letters to produce the correct tone. In polysyllabic words, an initial high class consonant with an implicit vowel renders the following syllable also high class.

There are a few exceptions to this system, notably the pronouns chan and khao, which are both pronounced with a high tone rather than the rising tone indicated by the script.


Thai distinguishes among three voice/aspiration patterns for consonants: unvoiced, unaspirated; unvoiced, aspirated; and voiced, unaspirated. Where English has only unvoiced, aspirated [p] and voiced, unaspirated [b], Thai distinguishes a third sound which is neither voiced nor aspirated, approximately the sound of the p in "spliced." There is similarly a [d], [th],[t] triplet. In the pharyngeal series there is a [k], [kh] pair and in the palatal a [c], [ch] pair.

  Voiced Unvoiced
Aspirated   kh, ch, th, ph
Unaspirated d, b k, c, t, p


The basic vowels of the Thai language, from back to front and high to low, are:

  front   back
high i (อิ, อี) ɨ (อึ, อื) u (อุ, อู)
  e (เอ)   o (โอ)
  æ (แอ)   ᴐ (ออ)
low   œ (เอิอ) a (อะ, อา)

The vowels each exist in short-long pairs: these are distinct phonemes forming unrelated words in Thai, but usually transliterated the same: เขา (khao) means he or she, while ขาว (khao) means white.

The short-long pairs are as follows:

Short Sound Long Sound
กะ u in "nut" กา a in "father"
กิ y in "greedy" กี ee in "see"
กุ oo in "look" กู ue in "blue"
เกะ e in "set" เก a in "lame"
แกะ a in "at" แก a in "ham"
กึ u in French "du" (short) กื u in French "dur" (long)
เกอะ u in "burn" (short) เกอ u in "burn" (long)
โกะ oa in "boat" โก ow in "bowl"
เกาะ o in "for" กอ aw in "raw"

The basic vowels can be combined into diphthongs as follows:

Short Sound Long Sound
ไก or ใก or ไกย I in "I" กาย I in "I" (stressed)
เกา ow in "cow" กาว ao in "Lao"
เกียะ ea in "ear" เกีย ea in "ear" (long)
กิว ew in "new" (short) -- --
กัวะ ure in "pure" (short) กัว ewe in "newer"
กุย uey in "bluey" กูย ooee in "cooee!"
เก็ว e in "set" + o in "poke" เกว a in "lame" + o in "poke"
-- -- แกว a in "ham" + o in "poke"
-- -- เกยอ u in French "dur" + a in "father"
-- -- เกย u in "burn" + y in "yes"
-- -- กอย oy in "boy" (long)
-- -- โกย oe in "Chloe"

Additionally, there are three triphthongs, all of which are long:

Spelling Sound
เกียว ee + aow
กวย oo + I in "I"
เกือย u in French "dur" + I in "I"

For a guide to written vowels, see the Thai alphabet page.


Other than compound words and words of foreign origin, most words are monosyllabic. Historically, words have most often been imported from Sanskrit and Pali; Buddhist terminology was a particularly fruitful source of these. Since the beginning of the 20th century, however, the English language has been the greatest influence.

Thailand also uses a distinctive six hour clock in addition to the 24 hour clock.


  • Segaller, Denis. Thai Without Tears: A Guide to Simple Thai Speaking. Bangkok: BMD Book Mags, 1999. ISBN 9748711528.

External links

  • Ethnologue write-up on Thai
  • Thai learning resources (
  • Websters Thai-English Dictionary
  • LEXiTRON Thai-English, English-Thai Dictionary
  • Parsit English-Thai Web Translation
  • Longdo Thai-English/French/German/Japanese Dictionary
  • Thai-English Transliteration and Dictionary
  • Thai Language Resources
  • Thai Particles (Large list of Thai particles with explanations and example sentences.)

Last updated: 02-10-2005 20:52:40
Last updated: 05-03-2005 17:50:55