Thai Vowels: Long, Short and Where They Go

Thai vowels are where most beginners get stuck. Not because there are many of them, but because they refuse to stay on the line. A Thai vowel can sit after the consonant, before it, above it, below it, or on two sides at once, and you still say the consonant first.

Once that clicks, vowels become the easy part of the script. They have one sound each, no exceptions worth worrying about, and most of them come in tidy long and short pairs. This guide covers where they go, how length works, the handful of vowels that change shape, and the order to learn them in.

How many vowels does Thai have?

The traditional count is 32 vowel forms. That number includes the long and short version of each vowel as separate forms, the diphthongs, and a few special combinations. They are built from about twenty basic symbols, so there is far less to memorise than 32 suggests.

Thai vowels have names the same way consonants do: the word sara (vowel) plus the sound. ◌า is sara aa, ◌ี is sara ii. The dotted circle in each one marks where the consonant goes.

Vowels are written around the consonant

Every vowel has a fixed position relative to the consonant it follows in speech. There are five places it can go:

The rule that makes this readable: find the consonant first, then collect the vowel around it. In เรียน the eye wants to start with the vowel sign on the left, but the word starts with ร, r. The vowel เ◌ีย wraps around it, and the final น, n, closes the syllable. R, ia, n: rian.

The vowels written before the consonant (เ◌, แ◌, โ◌, ใ◌ and ไ◌, and the longer vowels built on them) are the ones to watch, because they are the only ones that break the left-to-right order.

Long and short vowels

Most Thai vowels come in pairs: a short one and a long one. The long one is held for roughly twice as long, and the difference is part of the word. ดุ du means fierce; ดู duu means to look. เข้า means to enter; ข้าว means rice. Same consonants, same tone, different words.

The vowel names double the long vowel: sara a is short, sara aa is long. Everyday romanisation, the one on street signs, does not mark length at all: เข้า and ข้าว are both written khao. The Thai spelling shows the difference, which is one more reason to read the script rather than the transliteration.

Notice the pattern in the written forms: many short vowels are the long vowel plus ◌ะ (sara a) on the end. เ◌ is long, เ◌ะ is short. แ◌ is long, แ◌ะ is short. Learn the long vowel and you have most of the short one for free.

The sound ◌ึ / ◌ื has no equivalent in English. Say the oo of "food", then, without moving your tongue, spread your lips flat as if you were about to smile.

Diphthongs: three sounds that glide

Three vowels glide from one sound into another. Each has a short form too, but the short ones are so rare you can leave them for later.

• เ◌ีย ia: เรียน rian, to study.
• เ◌ือ uea: เสือ suea, tiger; เรือ ruea, boat.
• ◌ัว ua: หัว hua, head; วัว wua, cow.

The extra vowels

A few forms are traditionally counted as vowels even though each one includes an ending sound:

• ◌ำ am: ทำ tham, to do.
• ไ◌ and ใ◌ ai: ไป pai, to go; ใคร khrai, who. They sound exactly the same. ใ◌ is used in only about twenty words, which Thai children learn as a list. Every other ai is spelt with ไ◌.
• เ◌า ao: เขา khao, he or she; เก้า kao, nine.

Then there are four rare ones, ฤ, ฤๅ, ฦ and ฦๅ, which come from Sanskrit. You will meet ฤ in a handful of loanwords such as อังกฤษ ang-krit, English. ฦ and ฦๅ are obsolete. Recognise ฤ, skip the rest.

Try it yourself

Answer without scrolling back. The letters below are the ones this article just covered.

Vowels that change shape

This is the part that confuses people reading real text: some vowels change form, or disappear altogether, when the syllable ends in a consonant.

• ◌ะ turns into a small mark above. Short a before a final consonant is written as a little hook over the consonant: กัน kan, together.
• เ◌ะ and แ◌ะ swap ◌ะ for a mark on top, shaped like a small figure eight: เด็ก dek, child; แข็ง khaeng, hard.
• โ◌ะ vanishes. A short o with a final consonant is not written at all: คน khon, person; นก nok, bird. Two consonants side by side with no vowel between them usually means a hidden o.
• ◌ัว loses its top mark. หัว hua has it, but with a final consonant only the ว is left: สวย suai, beautiful; รวม ruam, to combine.
• เ◌อ changes too. Before ย it loses the อ: เลย loei, at all. Before other finals the อ becomes ◌ิ: เดิน doen, to walk.

There is one more hidden vowel. In some words a short a is spoken between two consonants but never written: สบาย sabai, well; ขนม khanom, dessert. You learn these word by word.

Words that start with a vowel

A Thai vowel cannot stand on its own. When a word starts with a vowel sound, it is written on the consonant อ (o ang), which is silent in that position and only holds the vowel's place: อ่าน an, to read; อิ่ม im, full.

So อ has two jobs. At the start of a syllable it is a silent carrier. After a consonant it is the long vowel sara aaw, as in รอ raw. Position tells you which.

Vowel length and tone

Vowel length does more than distinguish words. It also feeds into the tone. A syllable that ends on a short vowel, like แกะ kae, is a "dead" syllable, and dead syllables follow different tone rules from live ones. That is why the short and long pairs are worth learning properly rather than approximately: the length you read is also part of how you work out the tone. The guide to Thai tones covers how that works.

The order to learn them in

1. The common long vowels, in words. ◌า, ◌ี, ◌ู, เ◌, แ◌, โ◌ and ◌อ. These seven cover a large share of everyday reading.
2. The short partners. Mostly the long form plus ◌ะ, so they come quickly.
3. ไ◌, ใ◌, ◌ำ and เ◌า. Very common, and easy once you know they are vowels.
4. The diphthongs เ◌ีย, เ◌ือ and ◌ัว.
5. The shape changes. Only once you are reading real words, because that is the only place you will see them.

As with consonants, learn every vowel inside a word you can say out loud, not from a chart. How to read the Thai alphabet explains where vowels fit in the bigger picture.

Thai Trainer teaches all 32 vowel forms with recorded audio and an example word for each, alongside the 44 consonants, the tone marks and the numerals. The spaced repetition brings back the pairs you keep mixing up, like ◌ิ and ◌ี, until you stop mixing them up. That part is free, with no time limit.