Key takeaways
- Thai textbooks traditionally count 32 vowels: 18 short and 14 long, as 14 short–long pairs plus 4 unpaired short vowels.
- Nine of the pairs are simple vowels and three are diphthongs, such as เอีย and เอือ.
- Vowel signs sit before, after, above or below the consonant, or around it; a vowel that wraps around a cluster wraps the whole cluster.
- Some vowels are not written at all: an unwritten a in open syllables and o in closed ones, as in ถนน, 'road'.
- Length changes meaning and, in syllables with no final or a stop final, the tone, so learn each pair together.
Thai vowels have two features that English speakers are not used to: length, where a short and a long vowel are different sounds that make different words, and position, where the vowel sign can sit on any side of its consonant. This guide covers both, along with the vowels that are not written at all.
How many Thai vowels there are
Thai Wikipedia's article on vowel length gives the count used in standard Thai textbooks: 32 vowel sounds, 18 short and 14 long. They form 14 short–long pairs (28 sounds) plus 4 unpaired short vowels:
| Group | Pairs | Sounds |
|---|---|---|
| Simple vowels | 9 | 18 |
| Diphthongs: เอียะ–เอีย, เอือะ–เอือ, อัวะ–อัว | 3 | 6 |
| Extra vowels in pairs: ฤ–ฤๅ, ฦ–ฦๅ | 2 | 4 |
| Unpaired extra vowels: อำ, ไอ, ใอ, เอา | – | 4 |
| Total | 14 | 32 |
English Wikipedia adds that the script builds these from 21 traditionally named vowel symbol elements, used alone or in combination, and that ฦ and ฦๅ are obsolete.
The nine simple pairs
Each pair below is shown in its open-syllable form, with ◌ marking the consonant. The rough English comparisons come from Wikipedia's chart and are only approximations.
| Short | Sounds like | Long | Sounds like |
|---|---|---|---|
| ◌ะ | u in "nut" | ◌า | a in "father" |
| ◌ิ | y in "greedy" | ◌ี | ee in "see" |
| ◌ึ | oo in "look", lips unrounded | ◌ือ | oo in "goose", lips unrounded |
| ◌ุ | oo in "shoot" | ◌ู | oo in "too" |
| เ◌ะ | e in "neck" | เ◌ | a in "lame" |
| แ◌ะ | a in "at" | แ◌ | a in "ham" |
| โ◌ะ | oa in "boat" | โ◌ | o in "go" |
| เ◌าะ | o in "not" | ◌อ | aw in "saw" |
| เ◌อะ | e in "the" | เ◌อ | u in "burn" |
Notice how often the short form simply adds ◌ะ to the long one. Notice too that the official romanisation writes both members of each pair the same way, a and a, i and i, which is why romanised Thai cannot show length.
Where the signs go
Wikipedia describes vowel signs placed above, below, left or right of the consonant, or in combinations of those places. In practice:
- After: า, ะ, อ
- Above: ◌ิ, ◌ี, ◌ึ, ◌ื, ◌ั
- Below: ◌ุ, ◌ู
- Before: เ, แ, โ, ใ, ไ
- Around: เ◌าะ, เ◌ีย, เ◌ือ
A sign written before the consonant is still pronounced after it. And when a syllable starts with a consonant cluster, a vowel with parts on both sides wraps the whole cluster. An example is เฉพาะ, chapho, which Wiktionary glosses as "specific" or "particular" and pronounces ฉะ-เพาะ: the เ–าะ surrounds ฉพ, and the ฉ carries an unwritten a.
Vowels that change shape
Several vowels look different when a final consonant follows. From Wikipedia's chart:
| Open syllable | With a final consonant |
|---|---|
| ◌ะ | ◌ั◌ (mai han akat) |
| เ◌ะ | เ◌็◌ |
| แ◌ะ | แ◌็◌ |
| โ◌ะ | no sign at all: ◌◌ |
| ◌ัว | ◌ว◌ |
| เ◌อ | เ◌ิ◌ |
Hidden vowels
Some syllables have no written vowel. Wikipedia explains that the inherent vowel is a in open syllables and o in closed ones. Its example is ถนน, "road": three consonants, no vowel signs, read thanon, with a after ถ and o between the two น.
ไ, ใ and the other extra vowels
Both ไ and ใ spell ai. Wikipedia notes that mai malai (ไ) is used in most words and mai muan (ใ) in only twenty specific words, so the ใ words are worth learning as a short list. The other extras are ◌ำ, am, and เ◌า, ao.
When length is hard to see
Thai Wikipedia lists the forms that mislead learners. With a tone mark, the usually long ◌า, เ◌, แ◌ and ◌อ can be short, as in ช่าง, เก่ง, แท่น and ป้อม. The usually short ◌ำ, ไ◌, ใ◌ and เ◌า can be long, as in น้ำ, ไม้, ใต้ and เช้า. These are learned word by word.
Why length matters
Length is one of the four inputs to tone. A syllable ending in a short vowel is dead, which changes its base tone. Compare two mid-class syllables: กา, long and live, has a mid tone; กะ, short and dead, has a low tone. Thai consonant classes and Thai tones explained cover the other inputs.
Learning the vowels
Learn each short–long pair together, saying both aloud, starting with signs that sit after or above the consonant and leaving the wrap-around forms for last. Regal - Learn Thai Language practises vowels as a separate stage of its alphabet practice, alongside consonants, tone marks and syllables. It is one of our language-learning apps, and the Thai script beginner's guide puts vowels in context.
Good to know
Frequently asked questions
How many vowels does Thai have?
Where are vowels written in Thai?
What is the difference between ไ and ใ?
How do you read a Thai word with no written vowel?
Sources
- Thai script (opens in a new tab)Wikipedia — accessed
- ความยาวสระ (Vowel length) (opens in a new tab)Thai Wikipedia — accessed
- เฉพาะ (opens in a new tab)Wiktionary — accessed
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