Thai IPA transcription maps Thai script to International Phonetic Alphabet symbols, including the language’s five contrastive tones. Unlike many scripts, Thai tone is not written directly — it is computed from the interaction of the initial consonant’s class, any tone mark, the vowel length, and the syllable’s live/dead status.
How it works
The transcriber maps consonants and vowels to IPA, then derives tone from the classic Thai tone-rule table:
consonant classes: high (ข ส ห …) mid (ก จ ด …) low (ค ง น …)
syllable type: live = long vowel / sonorant final
dead = stop final / short vowel
tone marks: ่ (mai ek) ้ (mai tho) ๊ (mai tri) ๋ (mai chattawa)
examples:
mid class + no mark + live → mid tone (˧)
high class + no mark + live → rising tone (˩˩˦)
low class + mai tho → high tone (˦˥)
mid class + mai ek → low tone (˨˩)Each resolved tone is printed as IPA chao tone letters so the contour is unambiguous.
The five Thai tones and their IPA notation
Thai has five contrastive tones. In IPA, Chao tone letters are used to show the pitch contour:
| Tone name | IPA contour | Description |
|---|---|---|
| Mid | ˧ | Level, at the middle of the speaker’s range |
| Low | ˨˩ | Starts low and falls slightly |
| Falling | ˥˩ | Starts high and falls sharply to low |
| High | ˦˥ | Starts high, level or slightly rising |
| Rising | ˩˩˦ | Starts low, dips, then rises |
Consonant class: the key driver
Thai consonants are divided into three classes — high, mid, and low — and the class of the initial consonant is the starting point for every tone calculation. This is why Thai has 44 consonants that map to only 21 distinct sounds: many consonants are phonetically identical but differ in class, which changes the tone of the syllable they initiate.
For example, /kʰ/ (an aspirated velar stop) can be written with ข (high class) or ค (low class). The same vowel and final produce different tones depending on which letter begins the syllable.
Live and dead syllables
A live syllable ends in a long vowel or a sonorant (ม น ง ย ว ญ ร ล). A dead syllable ends in a short vowel with no final consonant, or in a stop final (ก ด บ and their variant spellings). Dead syllables have higher base tones and behave differently under the tone rules, particularly for low-class initials.
Extended example
ขา (kʰaː, “leg”) — high-class initial ข, long vowel า, sonorant-like open ending → live syllable, no tone mark → rising tone → /kʰaː˩˩˦/
ค่า (kʰâː, “value”) — low-class initial ค, long vowel า, mai ek ่ → falling tone → /kʰaː˥˩/
ขา and ค่า use phonetically identical sounds but the class of the initial consonant and the tone mark combine to produce entirely different tones. This is the essence of what the transcriber computes.
Provide clean, isolated syllables for the most reliable tone and segment output. The tool does not resolve the silencing mark (thanthakhat ์) or complex cluster reordering across syllables.