The Thai Vowels (Sara): Forms and How to Type Them

Thai vowels, called สระ (sara), are written around the consonant rather than in a line after it. A single vowel sound can sit before, above, below, or after its consonant — or surround it on several sides at once. On the keyboard that wrapping is a keystroke order, not a drawing problem: you press keys left to right in a fixed sequence, and the operating system stacks the marks. This is the part of Thai typing that feels strangest at first, and the part that rewards a little structure.

ThaiTyper’s skill track splits the sara into three atoms for that reason: trailing-vowels (า ะ ำ), stacked-vowels (ิ ี ึ ื ั ุ ู), and preposed-order (เ แ โ ใ ไ). Those twelve characters, plus ็ on Shift+H and ์ on Shift+N, are almost the whole working set. The positions below are Kedmanee positions from CHARS.kedmanee. If your OS is on Pattachote, none of the home-row claims in this article will match your fingers.

ThaiTyper’s cluster walk in lib/typing/clusters.ts is not a style guide. It is the same grouping the trainer uses to decide what Backspace deletes. A pre-posed vowel starts a cluster and swallows the next base. Combining marks attach to that base. Trailing ะ า ำ sit after it. If you treat the on-screen wrap as the typing order, Backspace will feel like it is deleting the wrong piece, which is exactly the failure the input-order article in this library exists to explain.

Four positions around the consonant

Vowels attach in four places: pre-posed (before the consonant on the line), above it, below it, and trailing (after it on the line). Some written vowels combine two or more of those positions to write one sound, so the consonant ends up wrapped on several sides. The typist’s job is not to draw the wrap. It is to emit the code points in the order the input engine expects.

The trainer’s cluster rules, in lib/typing/clusters.ts, are the ones to practise: a pre-posed vowel เ แ โ ใ ไ is typed first and absorbs the following base consonant; then any nonspacing marks — stacked vowels, tone marks, thanthakhat ์, maitaikhu ็ — stack onto that base; then trailing vowels such as ะ า ำ follow. Visual order on screen is not a reliable guide to that sequence, because เ prints to the left of ก in เก even though เ was the first key.

• Pre-posed, on the line to the left: เ แ โ ใ ไ. Typed first.
• Above the consonant: ิ ี ึ ื ั, plus the four tone marks and ็ ์ ํ when they appear.
• Below the consonant: ุ ู, and ฺ in the rare cases you need it (Shift+B on Kedmanee).
• Trailing, on the line to the right: ะ า ำ, and the second half of surrounding vowels such as the า in เา.
• The displayed cluster is one unit. Backspace removes code points from the end of the sequence, not “the mark you are looking at.”

Pre-posed vowels: เ แ โ ใ ไ

These five vowels are written to the left of the consonant even though they are pronounced as part of the same syllable after the initial sound. This is the single most important typing rule in Thai: you press the pre-posed vowel first, then the consonant. ThaiTyper’s preposed-order atom exists to make that sequence automatic. If you type ก then เ, the engine commits ก as its own cluster and then starts a new one with เ — you see กเ, which is not เก, and Backspace must remove both pieces.

Frequency is not evenly spread across the five. เ is the workhorse: เด็ก, เก, เดิน, เมือง, เป็น, เล่า. แ appears in แม่, แต่, แบบ, และ. โ in โต, โดย, โรง. ไ and ใ write the same /ai/ sound in different words — ไม่ ไป ไทย versus ใจ ใหม่ ใคร — and must be memorised as spelling, not sounded out. The pre-posed-first rule is identical for all five; the spelling choice between ไ and ใ is vocabulary.

ThaiTyper will not tell you which of ไ and ใ a word uses — that is spelling, not a keystroke rule. What it will do is fail the cluster if you type ไ on W when the prompt shows ใ, because those are different code points on different keys. ใ is period, right ring, bottom row. ไ is W, left ring, top row. The only reliable drill is a closed list: ไม่ ไป ไทย for ไ, ใคร ใจ ใหม่ for ใ, named keys, until the finger, not the ear, chooses the key.

• เก is เ then ก. If you see กเ, you typed the consonant first.
• ไม่ is ไ then ม then ่. Three keys, one of the most common words in Thai.
• ไป is ไ then ป. ป is on X (bottom row, left ring), ไ is on W (top row, left ring) — same finger, opposite rows.
• เด็ก is เ then ด then ็ (Shift+H) then ก. Maitaikhu is a stacked mark, so it comes after the consonant, not before เ.
• แก is แ then ก. และ is แ then ล then ะ — pre-posed, consonant, trailing.

Where they live on the keyboard

On Kedmanee the pre-posed vowels are spread across both hands but lean left. เ sits on G, home row, left index — no reach, the most common of the five, which is why the vowel-first habit gets practised every time you type เป็น or เด็ก. แ is on C, bottom row, left middle, one key down from ก on D. ไ is on W, top row, left ring, above ห on S. ใ is on period, bottom row, right ring, below ส on L. โ is Shift+F: the F key, which holds ด on its base, with right Shift held by the right pinky.

The physical logic is that the left index owns both เ on G and โ on Shift+F, two adjacent keys. แ on C belongs to the left middle, the same finger that types ก on D. ไ on W belongs to the left ring, above ห. ใ is the odd one out: it is the only pre-posed vowel on the right hand, on the period key, so a word such as ใจ is right-ring ใ then left-middle จ (Digit0) — a long jump, which is why ใ-words feel slower than ไ-words even though the sound is the same.

โ is the Shift of ด, not a neighbour of เ. Learners who think the long /o/ must live near เ on G will look at H or at F’s base and miss it. The chord is right Shift plus F; the left index stays on the F bump. Same-hand Shift — left Shift plus F — is how you get a delayed ด or a dropped Shift and no โ at all. The skill track’s shift-layer atom is later than preposed-order, so you meet เ แ ไ ใ as base keys first and โ as a Shift chord second. That split is intentional.

1. Type เ ten times on G without looking. Left index, home row. Do not double-tap; the rest position is the same key.
2. Type แ on C, returning the left middle to D (ก) after each press.
3. Type ไ on W, returning the left ring to S (ห).
4. Type โ as right Shift plus F, never left Shift plus F. Same-hand Shift is how ด appears instead of โ.
5. Type ใ on period with the right ring, then a left-hand consonant, to feel the handoff.

Above and below

Vowels like ◌ิ ◌ี ◌ึ ◌ื and ◌ั sit above the consonant, while ◌ุ and ◌ู sit below. These are combining marks: you type the consonant first and the vowel stacks onto it. A tone mark, if the syllable has one, goes on after the stacked vowel — consonant, then vowel, then tone. กี่ is ก then ี. กิ่ is ก then ิ then ่. Do not put the tone on before the stacked vowel; the orthography checker in the platform layer flags a mark-order issue when that happens.

Kedmanee positions, from the same table. Above: ั on Y (top row, right index), ี on U (top row, right index one step right), ึ on Digit7 (number row, right index), ื on N (bottom row, right index), ิ on B (bottom row, left index). Below: ุ on Digit6 (number row, right index), ู on Shift+Digit6. A notable pattern: the right index is responsible for ั ี ุ ึ — four of the seven stacked vowels. Training that one finger pays outsized dividends, which is why the stacked-vowels atom exists as its own skill rather than being mixed into reaches.

The pair that collides visually is ิ and ี. They look like the same stroke with a length mark on the latter, and they live on opposite sides of the keyboard: ิ on B (left index, down), ี on U (right index, up). Heatmaps that show both KeyB and KeyU hot are almost always this swap. ุ versus ู is a Shift-state error on the same physical key, Digit6: forget Shift and you get the short vowel, hold Shift with the wrong hand and you fumble the chord. Pause before any number-row Shift.

Mai han-akat ั on Y is not a short ะ. กัน is ก then ั then น — D, Y, O. กะ is ก then ะ — D, T. The two marks sit on adjacent top-row keys: T is left index (above เ on G), Y is right index. They write different syllables. Heatmaps that light KeyT and KeyY together are usually this swap, not a random number-row problem. ํ, nikkhahit, is Shift+Y on the same physical key as ั; the specials atom (ำ ั ์ ํ) exists because those four marks are easy to mix once stacked vowels are in play.