Thai numerals (Thai: , RTGS: lek thai, pronounced [lê:k tj]) are a set of numerals traditionally used in Thailand, although the Arabic numerals are more common due to extensive westernization of Thailand in the modern Rattanakosin period. Thai numerals follow the Hindu-Arabic numeral system commonly used in the rest of the world. In Thai language, numerals often follow the modified noun and precede a measure word, although variations to this pattern occur.
The Thai language lacks grammatical number. A count is usually expressed in the form of an uninflected noun followed by a number and a classifier. "Five teachers" is expressed as "teacher five person" khru ha khon (Thai: or with the numeral included Thai: ? .) Khon "person" is a type of referent noun that is also used as the Thai part of speech called in English a linguistic classifier, or measure word. In Thai, counting is kannap (; nap is "to count", kan is a prefix that forms a noun from a verb); the classifier, laksananam ( from laksana characteristic, form, attribute, quality, pattern, style; and nam name, designation, appellation.) Variations to this pattern do occur, and there really is no hierarchy among Thai classifiers. A partial list of Thai words that also classify nouns can be found in Wiktionary category: Thai classifiers.
Thai s?n is written as oval 0 (number) when using Arabic numerals, but a small circle ? when using traditional numerals, and also means centre in other contexts. It is from Sanskrit nya, as are the (context-driven) alternate names for numbers one to four given below; but not the counting 1 (number).
Thai names for N +1 and the regular digits 2 through 9 as shown in the table, below, resemble those in Chinese varieties (e.g., Cantonese and Min Nan) as spoken in Southern China, the homeland of the overseas chinese living in South East Asia . In fact, the etymology of Thai numerals 2, 3, 4, 6, 7, 8, 9, and 10 is Middle Chinese, while the etymology of Thai numeral 5 is Old Chinese, as illustrated in the table below
|1||?||nueng||/n/||? (ai)||Proto-Tai /n/|
|2||?||song||/s:?/||(yi)||Middle Chinese /sa?/ (compare Min Nan ? sang1) and /nyijH/ (compare Min Nan ? ji7)|
|3||?||sam||/s?:m/||(sam)||Middle Chinese /sam/ (compare Hakka/Cantonese ?sam1)|
|4||?||si||/sì:/||(sai)||Middle Chinese sijH (compare Min Nan ? si3)|
|5||?||ha||/hâ:/||? (ngua)||Old Chinese /*?a?/ (compare Min Nan ? ngo.)|
|6||?||hok||/hòk/||(lok)||Middle Chinese /ljuwk/ (compare Hakka + Cantonese ? liok8)|
|7||?||?||chet||/tèt/||? (chet)||Middle Chinese /tshit/ (compare Min Nan ? chit4)|
|8||?||paet||/p:t/||(paet)||Middle Chinese /peat/ (compare Cantonese ? pat4)|
|9||?||?||kao||/kâ:w/||(chao)||Middle Chinese /kjuwX/ (compare Min Nan ? kau2)|
|10||sip||/sìp/||(chong)||Middle Chinese dzyip (compare Min Nan (compare Hakka ? sip8)|
Numerical digit characters, however, are almost identical to Khmer numerals. Thai and Lao words for numerals are almost identical, however, the numerical digits vary somewhat in shape. Shown above is a comparison between three languages using Cantonese and Minnan characters and pronunciations. Shown below is a comparison between three languages using Khmer numerals. Thai and Lao. The Thai transliteration uses the Royal Thai General System of Transcription (RTGS).
|7||?||?||chet||/tèt/||? (chet)||?||/pram pi:/||?||?||/tét/|
Sanskrit lakh designates the place value of a digit (tamnaeng khong tua lek, ), which are named for the powers of ten: the unit's place is lak nuai (); ten's place, lak sip (?); hundred's place, lak roi (), and so forth. The number one following any multiple of sip becomes et (Cantonese, yat1; Minnan, it4). The number ten (sip) is the same as Minnan ? (sip8, lit.). Numbers from twenty to twenty nine begin with yi sip (Cantonese?, yi6sap6; Minnan?, lit. ji7sip8). Names of the lak sip for 30 to 90, and for the lak of 100, 1000, 10,000, 100,000 and million, are almost identical to those of the like Khmer numerals.
|11||?||sip et||/sìp ?èt/|
|12||sip song||/sìp s:?/|
|20||yi sip||/jî: sìp/|
|21||?||yi sip et||/jî: sìp ?èt/|
|22||yi sip song||/jî: sìp s:?/|
|30||sam sip||/s?:m sìp/|
|31||?||sam sip et||/s?:m sìp ?èt/|
|32||sam sip song||/s?:m sìp s:?/|
|10 000||muen||/m:n/||From Middle Chinese /mnH/ ?|
|1 000 000||?||?||lan||/lá:n/|
For the numbers twenty-one through twenty-nine, the part signifying twenty: yi sip (), may be colloquially shortened to yip (). See the alternate numbers section below.
The hundreds are formed by combining roi with the tens and ones values. For example, two hundred and thirty-two is song roi sam sip song. The words roi, phan, muen, and saen should occur with a preceding numeral (nueng is optional), so two hundred ten, for example, is song roi sip, and one hundred is either roi or nueng roi. Nueng never precedes sip, so song roi nueng sip is incorrect. Native speakers will sometimes use roi nueng (or phan nueng, etc.) with different tones on nueng to distinguish one hundred from one hundred and one. However, such distinction is often not made, and ambiguity may follow. To resolve this problem, if the number 101 (or 1001, 10001, etc.) is intended, one should say roi et (or phan et, muen et, etc.).
Numbers above a million are constructed by prefixing lan with a multiplier. For example, ten million is sip lan, and a trillion (1012, a long scale billion) is lan lan.
Colloquially, decimal numbers are formed by saying chut (, dot) where the decimal separator is located. For example, 1.01 is nueng chut sun nueng ().
Fractional numbers are formed by placing nai (, in, of) between the numerator and denominator or using [set] x suan y ( x ? y, x parts of the whole y) to clearly indicate. For example, 1⁄3 is nueng nai sam (?) or [set] nueng suan sam (). The word set () can be omitted.
The word khrueng () is used for "half". It precedes the measure word if used alone, but it follows the measure word when used with another number. For example, kradat khrueng phaen () means "half sheet of paper", but kradat nueng phaen khrueng () means "one and a half sheets of paper".
Negative numbers are formed by placing lop (, minus) in front of the number. For example, -11 is lop sip et ().
Ordinal numbers are formed by placing thi (, place) in front of the number. They are not considered a special class of numbers, since the numeral still follows a modified noun, which is thi in this case.
|thi nueng||/t?î: n/||first|
|thi song||/t?î: s:?/||second|
|thi sam||/t?î: s?:m/||third|
|thi si||/t?î: sì:/||fourth|
|#||thi #||/t?î:/||#st, #nd, #rd, #th|
Ek (Thai: ) is from Pali ?ka, "one"  Ek is used for one (quantity); first (rank), more prominent than tho second, in tone marks, education degrees and military ranks; and for the lead actor in a role. In antiquity, a seventh daughter was called luk ek (), though a seventh son was luk chet (?).
Et (Thai: ?, Cantonese, yat1; Minnan, it4), meaning "one", is used as last member in a compound number (see the main numbers section above).
Yi (Thai: , Cantonese, yi6; Minnan, ji7) is still used in several places in Thai language for the number two, apart from song (): to construct twenty (two tens) and its combinations twenty-one through twenty-nine; to name the second month, duean yi (), of the traditional Thai lunar calendar; and in the Thai northern dialect thin pha yip (?-), which refers to the Year of the Tiger.
Tri () and trai () are from Sanskrit tr?ya?, "three". These alternatives are used for three; third rank in tone marks, education degrees and military ranks; and as a prefix meaning three(fold).
Chattawa () is the Pali numeral four; used for the fourth tone mark and as a prefix meaning fourth in order or quadruple in number.
Yip (Thai: or ) in colloquial Thai is an elision or contraction of yi sip () at the beginning of numbers twenty-one through twenty-nine. Therefore, one may hear yip et (?, ?), yip song (, ), up to yip kao (?, ?). Yip may have a long vowel () or be elided further into a short vowel ().
The alternate set of numerals used to name tonal marks (, mai), educational degrees (, parinya), and military rankings derive from names of Sanskrit numerals.
|Number||Tonal Mark||Educational Degree||Military Ranking in the Royal Thai Army|
|ek||first||-?||mai ek||first tone||parinya ek||doctor's||phon ek||General|
|cha sip ek||Master Sgt. 1st Class|
|sip ek||Sergeant (Sgt.)|
|tho||second||-?||mai tho||second tone||parinya tho||master's||?||phon tho||Lieutenant General|
|phan tho||Lieutenant Colonel|
|cha sip tho||Master Sgt. 2nd Class|
|tri||third||-?||mai tri||third tone||parinya tri||bachelor's||phon tri||Major general|
|?||roi tri||Sub Lieutenant|
|cha sip tri||Master Sgt. 3rd Class|
|sip tri||Lance Corporal|
|chattawa||fourth||-?||mai chattawa||fourth tone||?||phon chattawa||Brigadier General (Honorary)|
[grammar] a classifier, a numerative noun