Punctuation

Minor pauses in sentences may be marked by a comma (Thai: จุลภาคCategory:Articles containing Thai-language text or ลูกน้ำCategory:Articles containing Thai-language text, chunlaphakCategory:Articles containing Thai-language text or luk namCategory:Articles containing Thai-language text), and major pauses by a period (Thai: มหัพภาคCategory:Articles containing Thai-language text or จุดCategory:Articles containing Thai-language text, mahap phakCategory:Articles containing Thai-language text or chutCategory:Articles containing Thai-language text), but most often are marked by a blank space (Thai: วรรคCategory:Articles containing Thai-language text, wakCategory:Articles containing Thai-language text). Thai writing also uses quotation marks (Thai: อัญประกาศCategory:Articles containing Thai-language text, anyaprakatCategory:Articles containing Thai-language text) and parentheses (round brackets) (Thai: วงเล็บCategory:Articles containing Thai-language text, wong lepCategory:Articles containing Thai-language text or Thai: นขลิขิตCategory:Articles containing Thai-language text, nakha likhitCategory:Articles containing Thai-language text), but not square brackets or braces.

A paiyan noiCategory:Articles containing Thai-language text ฯCategory:Articles containing Thai-language text (Thai: ไปยาลน้อยCategory:Articles containing Thai-language text) is used for abbreviation. A paiyan yaiCategory:Articles containing Thai-language text ฯลฯCategory:Articles containing Thai-language text (Thai: ไปยาลใหญ่Category:Articles containing Thai-language text) is the same as "etc." in English.

Several obsolete characters indicated the beginning or ending of sections. A bird's eye ๏Category:Articles containing Thai-language text (Thai: ตาไก่Category:Articles containing Thai-language text, ta kaiCategory:Articles containing Thai-language text, officially called ฟองมันCategory:Articles containing Thai-language text, fong manCategory:Articles containing Thai-language text) formerly indicated paragraphs. An angkhan kuuCategory:Articles containing Thai-language text ๚Category:Articles containing Thai-language text (Thai: อังคั่นคู่Category:Articles containing Thai-language text) was formerly used to mark the end of a chapter. A kho mutCategory:Articles containing Thai-language text ๛Category:Articles containing Thai-language text (Thai: โคมูตรCategory:Articles containing Thai-language text) was formerly used to mark the end of a document, but is now obsolete.

Consonants

There are 44 consonant letters representing 21 distinct consonant sounds. Duplicate consonants either correspond to sounds that existed in Old Thai at the time the alphabet was created but no longer exist (in particular, voiced obstruents such as d), or different Sanskrit and Pali consonants pronounced identically in Thai. There are in addition four consonant-vowel combination characters not included in the tally of 44.

Consonants are divided into three classes—in alphabetical order these are middle (กลางCategory:Articles containing Thai-language text, klang), high (สูงCategory:Articles containing Thai-language text, sung), and low (ต่ำCategory:Articles containing Thai-language text, tam) class—as shown in the table below. These class designations reflect phonetic qualities of the sounds to which the letters originally corresponded in Old Thai. In particular, "middle" sounds were voiceless unaspirated stops; "high" sounds, voiceless aspirated stops or voiceless fricatives; "low" sounds, voiced. Subsequent sound changes have obscured the phonetic nature of these classes.^{[nb 1]} Today, the class of a consonant without a tone mark, along with the short or long length of the accompanying vowel, determine the base accent (พื้นเสียงCategory:Articles containing Thai-language text, phuen siang). Middle class consonants with a long vowel spell an additional four tones with one of four tone marks over the controlling consonant: mai ek, mai tho, mai tri, and mai chattawa. High and low class consonants are limited to mai ek and mai tho, as shown in the Tone table. Differing interpretations of the two marks or their absence allow low class consonants to spell tones not allowed for the corresponding high class consonant. In the case of digraphs where a low class follows a higher class consonant, often the higher class rules apply, but the marker, if used, goes over the low class one; accordingly, ห นำCategory:Articles containing Thai-language text ho nam and อ นำCategory:Articles containing Thai-language text o nam may be considered to be digraphs as such, as explained below the Tone table.^{[nb 2]}

Notes

To aid learning, each consonant is traditionally associated with an acrophonic Thai word that either starts with the same sound, or features it prominently. For example, the name of the letter ขCategory:Articles containing Thai-language text is kho khai (ข ไข่Category:Articles containing Thai-language text), in which kho is the sound it represents, and khai (ไข่Category:Articles containing Thai-language text) is a word which starts with the same sound and means "egg".

Two of the consonants, ฃCategory:Articles containing Thai-language text (kho khuat) and ฅCategory:Articles containing Thai-language text (kho khon), are no longer used in written Thai, but still appear on many keyboards and in character sets. When the first Thai typewriter was developed by Edwin Hunter McFarland in 1892, there was simply no space for all characters, thus two had to be left out.^[6] Also, neither of these two letters correspond to a Sanskrit or Pali letter, and each of them, being a modified form of the letter that precedes it (compare ขCategory:Articles containing Thai-language text and คCategory:Articles containing Thai-language text), has the same pronunciation and the same consonant class as the preceding letter, thus making them redundant. They used to represent the sound /x/Category:Pages with plain IPA in Old Thai, but it has merged with /kʰ/Category:Pages with plain IPA in Modern Thai.

Equivalents for romanisation are shown in the table below. Many consonants are pronounced differently at the beginning and at the end of a syllable. The entries in columns initial and final indicate the pronunciation for that consonant in the corresponding positions in a syllable. Where the entry is '-', the consonant may not be used to close a syllable. Where a combination of consonants ends a written syllable, only the first is pronounced; possible closing consonant sounds are limited to 'k', 'm', 'n', 'ng', 'p' and 't'.

Although official standards for romanisation are the Royal Thai General System of Transcription (RTGS) defined by the Royal Thai Institute, and the almost identical ISO 11940-2 defined by the International Organization for Standardization, many publications use different romanisation systems. In daily practice, a bewildering variety of romanisations are used, making it difficult to know how to pronounce a word, or to judge if two words (e.g. on a map and a street sign) are actually the same. For more precise information, an equivalent from the International Phonetic Alphabet (IPA) is given as well.

Vowels

Thai vowel sounds and diphthongs are written using a mixture of vowel symbols on a consonant base. Each vowel is shown in its correct position relative to a base consonant and sometimes a final consonant as well. Vowels can go above, below, left of or right of the consonant, or combinations of these places. If a vowel has parts before and after the initial consonant, and the syllable starts with a consonant cluster, the split will go around the whole cluster.

Twenty-one vowel symbol elements are traditionally named, which may appear alone or in combination to form compound symbols.

Notes

The inherent vowels are /a/Category:Pages with plain IPA in open syllables (CV) and /o/Category:Pages with plain IPA in closed syllables (CVC). For example, ถนน transcribes /Category:Pages with plain IPAtʰCategory:Pages with plain IPAàCategory:Pages with plain IPAnCategory:Pages with plain IPAǒCategory:Pages with plain IPAnCategory:Pages with plain IPA/Category:Pages with plain IPA "road". There are a few exceptions in Pali loanwords, where the inherent vowel of an open syllable is /ɔː/Category:Pages with plain IPA. The circumfix vowels, such as เ–าะ /ɔʔ/Category:Pages with plain IPA, encompass a preceding consonant with an inherent vowel. For example, /Category:Pages with plain IPApʰCategory:Pages with plain IPAɔʔCategory:Pages with plain IPA/Category:Pages with plain IPA is written เพาะ, and /Category:Pages with plain IPAtɕʰCategory:Pages with plain IPAaCategory:Pages with plain IPApʰCategory:Pages with plain IPAɔʔCategory:Pages with plain IPA/Category:Pages with plain IPA "only" is written เฉพาะ.

The characters ฤ ฤๅ (plus ฦ ฦๅ, which are obsolete) are usually considered as vowels, the first being a short vowel sound, and the latter, long. The letters are based on vocalic consonants used in Sanskrit, given the one-to-one letter correspondence of Thai to Sanskrit, although the last two letters are quite rare, as their equivalent Sanskrit sounds only occur in a few, ancient words and thus are functionally obsolete in Thai. The first symbol 'ฤ' is common in many Sanskrit and Pali words and 'ฤๅ' less so, but does occur as the primary spelling for the Thai adaptation of Sanskrit 'rishi' and treu (Thai: ตฤๅCategory:Articles containing Thai-language text /trɯ̄ː/Category:Pages with plain IPA or /trīː/Category:Pages with plain IPA), a very rare Khmer loan word for 'fish' only found in ancient poetry. As alphabetical entries, ฤ ฤๅ follow ร, and themselves can be read as a combination of consonant and vowel, equivalent to รึ (short), and รือ (long) (and the obsolete pair as ลึ, ลือ), respectively. Moreover, ฤ can act as ริ as an integral part in many words mostly borrowed from Sanskrit such as กฤษณะ (kritsana, not kruetsana), ฤทธิ์ (rit, not ruet), and กฤษดา (kritsada, not kruetsada), for example. It is also used to spell อังกฤษ angkrit England/English. The word ฤกษ์ (roek) is a unique case where ฤ is pronounced like เรอ. In the past, prior to the turn of the twentieth century, it was common for writers to substitute these letters in native vocabulary that contained similar sounds as a shorthand that was acceptable in writing at the time. For example, the conjunction 'or' (Thai: หรือCategory:Articles containing Thai-language text /rɯ̌ː/Category:Pages with plain IPA rue, cf. Lao: ຫຼຶ/ຫລືCategory:Articles containing Lao-language text /lɯ̌ː/Category:Pages with plain IPA lu) was often written Thai: ฤCategory:Articles containing Thai-language text. This practice has become obsolete, but can still be seen in Thai literature.

The pronunciation below is indicated by the International Phonetic Alphabet^[7] and the Romanisation according to the Royal Thai Institute as well as several variant Romanisations often encountered. A very approximate equivalent is given for various regions of English speakers and surrounding areas. Dotted circles represent the positions of consonants or consonant clusters. The first one represents the initial consonant and the latter (if it exists) represents the final.

Ro han (ร หัน) is not usually considered a vowel and is not included in the following table. It represents the sara a /a/Category:Pages with plain IPA vowel in certain Sanskrit loanwords and appears as ◌รร◌. When used without a final consonant (◌รร), /n/Category:Pages with plain IPA is implied as the final consonant, giving /an/Category:Pages with plain IPA.

Notes

Tone

Central Thai

Central Thai is a tonal language, and the script gives full information on the tones. Tones are realised in the vowels, but indicated in the script by a combination of the class of the initial consonant (high, mid or low), vowel length (long or short), closing consonant (plosive or sonorant, called dead or live) and, if present, one of four tone marks, whose names derive from the names of the digits 1–4 borrowed from Pali or Sanskrit. The rules for denoting tones are shown in the following chart:

Symbol	Name		Syllable composition and initial consonant class
	Thai	RTGS	Vowel and final	Low	Mid	High
	(ไม่มี)	(none)	live long vowel or vowel plus sonorant	middle	middle	rising
	(ไม่มี)	(none)	dead short short vowel at end or plus plosive	high	low	low
	(ไม่มี)	(none)	dead long long vowel plus plosive	falling	low	low
่	ไม้เอก	mai ek	any	falling	low	low
้	ไม้โท	mai tho	any	high	falling	falling
๊	ไม้ตรี	mai tri	any	-	high	-
๋	ไม้จัตวา	mai chattawa	any	-	rising	-

"None", that is, no tone marker, is used with the base accent (พื้นเสียง, phuen siang). Mai tri and mai chattawa are only used with mid-class consonants.

Two consonant characters (not diacritics) are used to modify the tone:

• ห นำ ho nam, leading ho. A silent, high-class ห "leads" low-class nasal stops (ง, ญ, น and ม) and non-plosives (ว, ย, ร and ล), which have no corresponding high-class phonetic match, into the tone properties of a high-class consonant. In polysyllabic words, an initial mid- or high-class consonant with an implicit vowel similarly "leads" these same low-class consonants into the higher class tone rules, with the tone marker borne by the low-class consonant.
• อ นำ o nam, leading o. In four words only, a silent, mid-class อ "leads" low-class ย into mid-class tone rules: อย่า (ya, don't) อยาก (yak, desire) อย่าง (yang, kind, sort, type) อยู่ (yu, stay). All four have long-vowel, low-tone siang ek; อยาก, a dead syllable, needs no tone marker, but the three live syllables all take mai ek.

Low consonant	High consonant	IPA
ง	หง	/ŋ/
ญ	หญ	/j/
น	หน	/n/
ม	หม	/m/
ย	หย	/j/
ร	หร	/r/
ล	หล	/l/
ว	หว	/w/
Low consonant	Middle consonant	IPA
ย	อย	/j/

In some dialects there are words which are spelled with one tone but pronounced with another and often occur in informal conversation (notably the pronouns ฉัน chan and เขา khao, which are both pronounced with a high tone rather than the rising tone indicated by the script). Generally, when such words are recited or read in public, they are pronounced as spelled.

Southern Thai

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Although the Southern Thai writing form also gives full information on the tones as does Central Thai, the language itself is a pitch-accent language, whose spoken form can have up to seven tones.^[8] When Southern Thai is written in Thai script, there are different rules for indicating spoken tone.

Tones	Nakhon Si Thammarat accent rules			IPA
First tone	An initial consonant class "high" with long sound, and an initial consonant class "low" after the word.			[˦˥˧]Category:Pages with plain IPA
	An initial consonant class "high" with short sound, and an initial consonant class "low" with [k̚], [t̚], [p̚] finals after the word.			[˨˦]Category:Pages with plain IPA
Second tone	An initial consonant class "high" both short long sound, and an initial consonant class "low" after the word.			[˦]Category:Pages with plain IPA
Third tone	An initial consonant class "middle" long sound.			[˧˦˧]Category:Pages with plain IPA
	An initial consonant class "middle" short sound with [k̚], [t̚], [p̚] finals.			[˧˦]Category:Pages with plain IPA
Fourth tone	An initial consonant class "middle" both short long sound.			[˧]Category:Pages with plain IPA
Fifth tone	An initial consonant class "low" with head word.			[˨˧˨]Category:Pages with plain IPA
Sixth tone	An initial consonant class "low" long sound.			[˨˦]Category:Pages with plain IPA
Seventh tone	An initial consonant class "low" short sound.			[˨˩]Category:Pages with plain IPA

Diacritics

Other diacritics are used to indicate short vowels and silent letters:

• Mai taikhu means "climbing stick". It is a miniature Thai numeral 8 ๘. Mai taikhu is often used with sara e (เ) and sara ae (แ) in closed syllables.
• Thanthakhat is an archaic word for "capital punishment"

Fan nu means "rat teeth" and is thought as being placed in combination with short sara i and fong man to form other characters.

Numerals

For numerals, mostly the standard Hindu-Arabic numerals (Thai: เลขฮินดูอารบิกCategory:Articles containing Thai-language text, lek hindu arabik) are used, but Thai also has its own set of Thai numerals that are based on the Hindu-Arabic numeral system (Thai: เลขไทยCategory:Articles containing Thai-language text, lek thai), which are mostly limited to government documents, election posters, license plates of military vehicles, and special entry prices for Thai nationals.

Other symbols

Pai-yan noi and angkhan diao share the same character. Sara a (–ะ) used in combination with other characters is called wisanchani.

Some of the characters can mark the beginning or end of a sentence, chapter, or episode of a story or of a stanza in a poem. These have changed use over time and are becoming uncommon.

Plosives (vargaḥ)

Plosives (also called stops) are listed in their traditional Sanskrit order, which corresponds to Thai alphabetical order from ก to ม with three exceptions: in Thai, high-class ข is followed by two obsolete characters with no Sanskrit equivalent, high-class ฃ and low-class ฅ; low-class ช is followed by sibilant ซ (low-class equivalent of high-class sibilant ส that follows ศ and ษ.) The table gives the Thai value first, and then the IAST (International Alphabet of Sanskrit Transliteration) value in square brackets.

None of the Sanskrit plosives are pronounced as the Thai voiced plosives, so these are not represented in the table. While letters are listed here according to their class in Sanskrit, Thai has lost the distinction between many of the consonants. So, while there is a clear distinction between ช and ฌ in Sanskrit, in Thai these two consonants are pronounced identically (including tone). Likewise, the Thai phonemes do not differentiate between the retroflex and dental classes, since Thai has no retroflex consonants. The equivalents of all the retroflex consonants are pronounced identically to their dental counterparts: thus ฏ is pronounced like ต, ฐ is pronounced like ถ, ฑ is pronounced like ท, ฒ is pronounced like ธ, and ณ is pronounced like น.

The Sanskrit unaspirated unvoiced plosives are pronounced as unaspirated unvoiced, whereas Sanskrit aspirated voiced plosives are pronounced as aspirated unvoiced.

Non-plosives (avargaḥ)

Semivowels (กึ่งสระ kueng sara) and liquids come in Thai alphabetical order after ม, the last of the plosives. The term อวรรค awak means "without a break"; that is, without a plosive.

Vowels

All consonants have an inherent 'a' sound, and therefore there is no need to use the ะ symbol when writing Sanskrit. The Thai vowels อื, ใอ, and so forth, are not used in Sanskrit. The zero consonant, อ, is unique to the Indic alphabets descended from Khmer. When it occurs in Sanskrit, it is always the zero consonant and never the vowel o [ɔː]Category:Pages with plain IPA. Its use in Sanskrit is therefore to write vowels that cannot be otherwise written alone: e.g., อา or อี. When อ is written on its own, then it is a carrier for the implied vowel, a [a]Category:Pages with plain IPA (equivalent to อะ in Thai).

The vowel sign อำ occurs in Sanskrit, but only as the combination of the pure vowels sara a อา with nikkhahit อํ.

Other non-Thai symbols

There are a number of additional symbols only used to write Sanskrit or Pali, and not used in writing Thai.

Visarga

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The means of recording visarga (final voiceless 'h') in Thai has reportedly been lost, although the character ◌ะ which is used to transcribe a short /a/ or to add a glottal stop after a vowel is the closest equivalent and can be seen used as a visarga in some Thai-script Sanskrit text.

Sukhothai consonant inventory

Historical Sukhothai pronuncation