An insatiable appetite for ancient and modern tongues

Alternative Names: Siamese, Central Thai.

Classification: Tai-Kadai, Tai, Southwestern. Thai is related to Lao of Laos, to Shan of Myanmar and to several languages of north Vietnam.

Overview. Thai is the largest of the Tai-Kadai languages, once thought to belong to Sino-Tibetan, but considered now an independent family. The ancestral home of the Thais might have been in the area straddling the border between northern Vietnam and southeastern China. From there, they migrated into central Thailand in the 13th century where they founded Sukhothai, their first major kingdom, and converted to Theravada Buddhism. Like all Tai-Kadai languages, Thai is monosyllabic and tonal, having no inflectional morphology.

Distribution and Speakers. Thai is spoken in all regions of Thailand by about 56 million people or 80 % of the population of the country (70 million). Some Thai nationals speak other languages of the Tai family and others are minorities who speak non-Tai languages.

Status. Thai is the official national language of Thailand. It is used in schools, the media and the government.


Varieties. Standard Thai is spoken in Bangkok and the central plains, Northern Thai (Kam Muang or Yuan) in the north, Southern Thai in the south, and Northeastern Thai (Lao, Isan) in the north-east. Some authors consider some or all non-Standard Thai varieties as separate languages.


Sukhotai era (mid-13th c.-mid-14th c.). In the kingdom of Sukhotai, Thai resembled Proto-Tai in tonal structure. Syllables ending in a vowel or in a nasal consonant had three tones, as it is still reflected in the writing system created at the time by king Ramkhamhaeng (1275-1317).

Ayutthaya era (mid-14th c.-mid-18th c.). The capital shifted southwards to Ayutthaya where occurred a tone split leading to the current five-tone system. Following the split, some initial consonants also changed.

Bangkok era (mid-18th c. to the present). Once more the capital shifted southwards, this time to Bangkok where the language became standardized and acquired a national dimension.

Oldest Documents                                                          

  1. Purportedly, the Ramkhamhaeng Inscription, dated 1292, is the earliest Thai document known. Engraved in a stone stele preserved in the Bangkok Museum, it contains a biography of the third king of the Sukhotai dynasty. Its authenticity is, however, doubtful.

  1. Other inscriptions of the Sukhotai period amount to 20,000 words. Among them, the inscriptions of Wat Sichum and Wat Pamamuang. The first gives an account of the origin of the dynasty, the foundation of the city of Sukhotai and the construction of a stupa to honor Buddha's relics. The second, inscribed in four tablets, is trilingual (Thai, Khmer and Pali); it contains a record of the establishment of religious monuments and a forest monastery for the retirement of King Lithai.

  1. Suphasit Phraruang (Maxims of King Ruang) is the earliest example of Thai didactic poetry.


Thai is essentially monosyllabic. Non-monosyllabic words are either loans or compounds. A syllable consists of a vocalic nucleus (short or long vowel) and a tone. In addition, one or two initial consonants and/or a final consonant (frequently a nasal) may or may not occur.

Vowels (18). Thai has three front vowels and six back vowels, the latter divided into rounded and unrounded. Each vowel may be short or long. The long vowels have a duration of about twice as long as the short vowels. Vowel length is phonemic.


Each of the high vowels (short or long) can be followed by a to produce the diphthongs ia, ɨa, ua. In most of them the first vowel is long.


Consonants (20-21). Thai has twenty consonants plus a glottal stop whose phonemic status is debatable. Stops and affricates may be unaspirated or aspirated (the latter represented by an h superscript).


-All twenty consonants may appear in initial position.

-In final position only p, t, k, m, n, ŋ, w, j  occur, and no consonant clusters are allowed.

-The glottal stop appears before a vowel that lacks an initial consonant or after a short vowel not  followed by a final consonant.

Tones. Thai is a tonal language and its tones are phonemic, serving to make lexical distinctions. Each syllable in Thai carries one of five tones: mid (unmarked), low (grave accent), falling (circumflex accent), high (acute accent) and rising (inverted circumflex accent). In addition to these five tones there is a variant of the high tone (higher and longer), used in emphatic utterances, that may replace any one of the other tones (marked with a tilde).

Stress. It falls on the final syllable.

Script and Orthography

      Thai is written with an alphabetic script that derives, ultimately, from the Brāhmī script of India. Its creation is credited to King Ramkhamhaeng of Sukhotai who, a few years before 1292 (date of the earliest extant Thai inscription), borrowed the characters from Khmer (also derived from Brāhmī) adding a number of new ones.

     He preserved symbols for Sanskrit sounds, useful for the many Sanskrit loanwords that have crept into Thai. Among the new symbols he included those for tones and Thai sounds absent in the original script. He also divided the consonants of the new alphabet into high, mid and low in order to indicate tone in spelling. As a consequence, many characters in the Thai alphabet are redundant i.e., some sounds have more than one character. It has no independent vowel signs, the vowel signs are diacritics placed above, below, to the right or to the left of a consonant.

    Below each character its transliteration is shown; it corresponds to the conventions of the International Phonetic Alphabet except that [tʃ] is transliterated c, [tʃʰ] is transliterated ch, [j] is transliterated y.



  1. Derivational

  2. New words can be produced from other words by several derivational processes like affixing, compounding and reduplication.

  1. 1.affixing includes the addition of one of a restricted number of special prefixes or suffixes to nouns and verbs. For example, kaan- and khwaan- are prefixes used to form abstract nouns from verbs, and nák- adds the meaning of expertise:

  1. kaan + lên ('to play') = kaanlên ('playing')

  2. nák- + rian ('to study') = nákrian ('student')

  1. 2.compound words may include nouns, adjectives, numerals and verbs. The head of the compound is usually the first constituent and all others are modifiers.

  1. nám ('water') + khɛ̌ŋ ('to be hard') = námkhɛ̌ŋ ('ice')

  2. rooŋ ('hall') + rian ('to study') = rooŋrian ('school')

  3. kὲε ('dark') + fay ('fire') = kὲεfay ('scorched')

  4. hâa ('five') + sìp ('ten') = hâasìp ('fifty')

  1. There are compounds that have two semantic heads:

  1. phɔ̂ɔ ('father') + mɛ̂ɛ ('mother') = phɔ̂ɔmɛ̂ɛ ('parents')

  1. 3.reduplication consists of a repetition of a word or part of a word. Thai has three types:

  1. Reduplication without changes, in order to make a plural, intensify meaning or sometimes attenuate it, or create onomatopoeic words:

  1. dèk = child → dèkdèk = children

  1. Reduplication with vowel change in which the duplicated syllable has a different vowel than that of the base word, in order to expand its meaning:

  1. chaŋ = to hate → chiŋchaŋ = to hate, detest, loathe

  1. Reduplication with emphatic high tone. The base word keeps its tone but the reduplication carries the emphatic variant of the high tone to enhance meaning:

  1. rɔ́ɔn = hot → rɔ̃ɔnrɔ́ɔn = blazing

  2. dii = good → dĩidii = excelent

  1. Nominal

  2. Most nouns are monosyllabic. They are not inflected for case, gender or number.

  1. When referring to more than one object, each noun should be accompanied with its proper noun classifier. Thai has more than 200 classifiers which do not have any obvious semantic correlation with their nouns. For example, khon is a classifier for human beings; tua for animals, clothes and furniture; lêm for knives, needles, books; tôn for trees, poles, blades of grass, etc. The order is noun + quantifier + classifier:

  1. dèk sǎam khon

  2. child three CL

  1. Possession can be indicated by juxtaposition of two nouns. The noun following the head noun is the possessor and the head noun the possessed. Alternatively, a preposition may be inserted to make the relation explicit.

  1. Thai has a complex pronoun system which distinguishes age, sex, social position and attitude of the speaker. Kinship terms frequently replace personal pronouns.

  1. a) Male speaker

  2. Polite conversation

  3. 1st person: phǒm

  4. 2nd person: khun

  1. Addressing a superior

  2. 2nd person: thân

  1. Informal conversation

  2. 1st person: chãn

  3. 2nd person: thəə

  1. b) Female speaker

  2. 1st person: dichãn

  3. 2nd person: khun

  1. Addressing a superior

  2. 2nd person: thân

  1. c) Adult speaking to child

  2. 1st person: chãn

  3. 2nd person: nǔu

  1. d) Child speaking to an adult

  2. 1st person: nǔu

  3. 2nd person: kinship term

  1. 3rd persons: khãw is the general polite form, man for an inferior, thân for a respected third person.

  2. Several of these pronouns can be used equally for singular and plural but raw is specific for the 1st person plural.

  3. Demonstrative pronouns distinguish three degrees: proximal (nîi = this one), intermediate (nân = that one) and distal (nôon = that distant); they can be used to express definiteness. Demonstrative adjectives are: níi (this), nán (that), nóon (that yonder).

  1. Interrogative and indefinite pronouns are formally identical. They include: khray ('who?, anyone'), àray ('what?, anything'), ny ('which?'), thîi ny ('where?, anywhere'), day ('which?, what?, any').

  1. Verbal.

  2. Thai verbs are not inflected for tense and number. The simple present is expressed by the verb alone. Other tenses by the use of particles or expressions of time. For example, the present continuous by adding the particle yùu after the main verb, the past tense by adding the particle dây before the verb, the past perfect  by adding lέεw and/or mah at the end of  the phrase.

  1. Serial verb constructions, composed by a main verb modified by secondary verbs, are frequent. There are two classes of secondary verbs, one precedes the main verb and the other follows it. In some serial verb constructions both kinds of secondary verbs are used, in other constructions just one or the other.

  1. First class verbs are equivalent to modal verbs or adverbs. Some modal verbs are tɔ̂ŋ ('must'), khuan ('should', 'ought'), àat ('to be capable of'), yàak ('to wish to'), ('shall', 'will'). For example:

  1. khǎw    tɔ̂ŋ     klàp    bâan

  2.   he      must  return  home

  1. Second class verbs usually indicate completion of the action initiated by the main verb.

  1. dèk wîng pay sɨɨ khanǒm

  2. child run  go buy candy

  1. The child ran and bought candy


The most common word order is Subject-Verb-Object. Attributive adjectives follow their nouns. Due to lack of inflections, syntactical functions are determined, mainly, by word order and prepositions. The order of the noun phrase is:

  1. noun-adjective-numeral-classifier-demonstrative

  2. dèk        lɔɔ        sǎam      khon         níi

  3. child   handsome   3          CL         these

  1. These three children are handsome.

In the verb phrase the verb may be followed by its object and/or its complements (to indicate place, time, direction of action, etc). Particles at the end of a phrase are used to pose a question (máy, rɨ̌ɨ, chây máy) or convey politeness (khâ used by a woman, khráp used by a man) or mood ( for persuading, rɔ̀ɔk to soften a statement, ləəy to encourage the addressee to do something).


Sanskrit and Pali loanwords constitute a sizable part of the technical vocabularies for science, government, education, religion and literature. Thai has also borrowed from Chinese though Chinese loanwords might be difficult to detect due to similarities between the two languages. There are also traces of Persian, Portuguese and French loanwords. More recently, English has contributed modern technical and scientific words.

Basic Vocabulary. As transliteration systems for Thai are incomplete or inconsistent we write the words with phonetic notation. Mid-tone is unmarked, low tone is marked with a grave accent, high tone with an acute accent, rising tone with an inverted circumflex accent, falling tone with a circumflex accent.

one: nɨ̀ŋ

two: sɔ̌ɔŋ

three: sǎ̌am

four: sìi

five: hâa

six: hòk

seven: cèt

eight: pὲ̀ɛt

nine: kâaw

ten: sìp

hundred: rɔ́ɔy

father: phɔ̂ɔ

mother: mε̂ɛ

elder brother/sister: phîi

younger brother/sister: nɔ́ɔŋ

child: lûuk

son: lûuk chaay

daughter: lûuk sǎaw

head: hǔa

eye: taa

foot: tháaw

heart: cay

tongue: lin

Key Literary Works

1400-1500    Lilit phra Lo (The Story of Prince Lo). Anonymous

  1. A tragic romance, based on various folktales, relating the seduction through magic of the handsome Prince Lo by two princesses of an enemy kingdom ending with the murder of all the lovers at the hands of the vengeful grandmother of the princesses.

1650-1700    Nirat Khlong Kamsuan (A Mournful Journey). Siprat

  1. This long lyrical poem is a masterpiece of the nirat genre characterized by journeying, longing and separation. In it, a courtier recounts his journey into exile to southern Thailand and the longing for his beloved and for Ayutthaya city.

1797-1807    Ramakian. Anonymous

  1. Based on the famous Indian epic Ramayana, the Thai version known as Ramakian (or Ramakien) was written down for the first time in the 18th century during the Ayutthaya period but it was destroyed in the sacking of Ayutthaya by the Burmese in 1767. Between 1797 and 1807 another version was prepared, under the supervision of king Rama I, which exerted a major influence on stage performances like the shadow play, danced-drama and masked-drama.

1810-1855    Phra Apaimani. Suntorn Phu (1786-1855)

  1. A very popular 30,000 line epic romance in which the princely hero is seduced by a beautiful woman who changes into a sea-witch and carries him to her under-sea kingdom.

  1. 1937    Khang lang phap (Behind the Painting). Siburapha (Kilap Sipradit)

  2. Narrated by a Thai student in Japan, with the use of flashback, this short novel tells of his doomed love affair with an older Thai aristocrat visiting the country with her husband. More realistic than other love-stories, the characters are precisely portrayed and their emotions are believable.

  1. 1969    Fa bo kan (The Politician and Other Stories). Khamsing Srinawk

  2. A collection of short stories with peasants as protagonists, depicted with subtle realism and irony.

  1. 1969    Chotmai Chak Muang Thai (Letters from Thailand). Botan (Supa Sirising)

  2. In 1945 Tan Suang U migrates from China into Bangkok looking for a better future. From there he writes letters to his mother in China over a period of twenty years telling her about his difficulties to adapt to Thai society in spite of his economic success.

  1. 1982    Kham phiphaksa (The Judgment). Chart Korbjitti

  2. In a small rural community, a relationship between a well-intentioned janitor and a widow, who happens to be his father's wife, turns into a scandal when everybody gossips and passes judgement.

  1. © 2013 Alejandro Gutman and Beatriz Avanzati                                                                               

Further Reading

  1. -'Thai'. Th. J. Hudak. In The World’s Major Languages, 660-676. B. Comrie (ed). Routledge (2009).

  2. -Thai Reference Grammar. R. B. Noss. Foreign Service Institute (1964).

  3. -Thai: An Essential Grammar. D. Smyth. Routledge, London (2002).

  4. -A Reference Grammar of Thai. S. Iwasaki & P. Ingkaphirom. Cambridge University Press (2005).

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