The Four Thai Tone Marks and What They Actually Do
TL;DR: Thai has four tone marks, ไม้เอก, ไม้โท, ไม้ตรี and ไม้จัตวา, and none of them names a tone. A mark selects a row in the tone rules table; the class of the consonant underneath decides what comes out of that row. The same mark gives low on one letter and falling on another. Phayan introduces the marks alongside a class in its free level 4. ThaiPod101 covers them as a chart.
The thing a tone mark is not
Almost every beginner arrives at the tone marks with a reasonable expectation and leaves with a wrong one. The expectation is that a language with five tones and four marks has given four of them a written symbol and left the fifth as the default, the way an accent works in French or Vietnamese. It is a sensible guess. It is also wrong, and it will quietly corrupt every word you read until you replace it.
Here is the demonstration, and it takes two words. ก่า and ค่า carry the same mark, the small stroke above the initial. The first is low tone. The second is falling. Nothing about the mark changed. What changed is the letter it is sitting on: ก is mid class, ค is low class, and the class is what decided which tone the mark produced.
So a Thai tone mark is not a label. It is closer to a switch. It tells you which row of a lookup table to read, and the consonant class tells you which column, and the tone is where they meet. That table is the subject of the Thai tone rules; this page is about the four marks that feed it, what they are actually called, where they sit, and the specific ways they surprise people.
The four marks, by name
Learn the Thai names rather than the English ones. Not out of purism, but because the English names in circulation are wrong: sources routinely call ไม้เอก the “low tone mark”, which is true for two thirds of the alphabet and false for the rest, and a name that is false a third of the time is worse than no name. The Thai names carry no such claim. They are just first, second, third and fourth.
| Mark | Thai name | Romanised | Literally | Shape |
|---|---|---|---|---|
| ◌่ | ไม้เอก | mai ek | stick one | a single upright stroke |
| ◌้ | ไม้โท | mai tho | stick two | a small curl, like a tiny 2 |
| ◌๊ | ไม้ตรี | mai tri | stick three | a shape like a small 3 |
| ◌๋ | ไม้จัตวา | mai chattawa | stick four | a small cross or plus |
Ek, tho, tri and chattawa are the Pali-derived numbers one to four, and mai here means a stroke or stick, the same word used for the strokes in other diacritics. So the four marks are named exactly what they are: the first stroke, the second stroke, the third and the fourth. That is the whole naming system, and it is a relief once you stop expecting the names to describe sounds.
Where a mark sits on the syllable
A tone mark is written above the initial consonant, and that placement is a fact worth holding on to, because it is what tells you which consonant is doing the tonal work in a syllable with several.
In ป้า (pâa, aunt) the mark sits over ป, the initial, not over the vowel that follows it. In น้ำ (náam, water) it is over น. When an above-vowel is already in that space, the tone mark stacks on top of it and the syllable grows a second storey: สี่ (sìi, four) is ส with the vowel อี and ไม้เอก sitting above it. A vowel and a tone mark is as tall as an ordinary syllable gets, so two storeys is the ceiling rather than the start of a pile.
Two placements are worth naming because they look like exceptions and are not. When a syllable begins with a cluster, the mark goes over the second letter of the cluster, as in เปล่า (plào, empty, or “no”), but the tone is still computed from the first letter’s class. And where a silent ห leads a low-class letter to make it behave as high class, the mark goes over the letter after the ห, as in ใหม่ (mài, new). In both cases the mark is placed where it fits and the class that matters is the one at the front of the syllable.
The same mark, three different tones
Here is what a mark actually does, laid out on all three consonant classes. Read across a row and you get the marks; read down a column and you get the point of this page.
| Class | No mark, live | ไม้เอก | ไม้โท | ไม้ตรี | ไม้จัตวา |
|---|---|---|---|---|---|
| Mid (ก จ ด ต บ ป อ …) | Mid | Low | Falling | High | Rising |
| High (ข ฉ ถ ผ ฝ ส ห …) | Rising | Low | Falling | not used | not used |
| Low (ค ง ช ท น พ ม ย ร ล ว …) | Mid | Falling | High | not used | not used |
The ไม้เอก column is the one to stare at. On a mid-class letter it gives low; on a high-class letter it also gives low; on a low-class letter it gives falling. One mark, two outcomes, decided entirely by a property of the letter that you cannot hear. ไม้โท does the same thing one step further up: falling on mid and high, high on low.
Real words make it concrete. ไม่ (mâi, not) is ม, low class, with ไม้เอก: falling. ใหม่ (mài, new) is the same ม with a silent ห in front making it count as high class, and the same ไม้เอก: low. Two words, one mark, one consonant sound, two tones, and the entire difference is a letter that is not pronounced. That pair is why “ไม้เอก means low tone” is not a shortcut you can afford.
Why you will barely see the third and fourth marks
ไม้ตรี and ไม้จัตวา are rare, and rare in a specific way that is useful to understand: they are, in practice, mid-class only. Look at the table again and you can work out why. A mid-class initial is the one letter class that can reach all five tones by marking alone: mid unmarked, low with ไม้เอก, falling with ไม้โท, and then it needs two more marks to reach high and rising. High-class and low-class letters reach those two tones another way, through the unmarked forms and through pairing with each other, so they never needed the extra marks and never took them.
That leaves ไม้ตรี and ไม้จัตวา doing a narrow job on nine mid-class letters, plus a handful of loanwords and expressive spellings that ignore the pattern. You will meet ไม้ตรี early anyway, because it sits in one of the most useful words in the language: โต๊ะ (tó, table). ไม้จัตวา is rarer still, showing up in words like เดี๋ยว (dǐao, in a moment). Neither is worth drilling in isolation. Meet them in the words that carry them.
The practical consequence for a reader is a pleasant one. Two thirds of the alphabet only ever takes two marks, so most of the time you are choosing between three states, no mark, ไม้เอก, ไม้โท, and not five.
How to actually learn them
Not as four symbols with four meanings, because that is the misconception this page exists to remove. Learn a mark attached to a class. “ไม้เอก on a mid-class letter” is one learnable unit that reliably gives low; “ไม้เอก on a low-class letter” is a different unit that reliably gives falling. Six or so of these pairings cover ordinary text, and each of them is a thing you can drill on real words.
Do that and the recognition arrives before the arithmetic does. You will find yourself reading ไม่ as falling without passing through “ม, low class, ไม้เอก, falling”, in the same way that you read a familiar English word without spelling it. The table stays available underneath for the words you have not met.
Phayan is an app for learning to read Thai script, and this is the shape its level 4 takes: the mid class and the tone marks arrive together, in the free part of the path, so the first thing you drill is a mark on a letter rather than a mark on its own. Words are built letter by letter with a typing engine that checks each pick as you make it, so choosing the wrong mark is caught at the moment you choose it rather than at the end of the word. Items come back for review at 1, 3, 7 and 21 days, three correct in a row marks one as learned, and a wrong answer restarts its ladder. Progress is kept on your device with no account. Beyond the free levels it is $14.99 a month or $79.99 a year on the web.
One limit to state plainly, because it bears on what any app can do for you here: the audio in Phayan is synthesised rather than recorded by a person. It is good for attaching a sound to a letter and for drilling which of the five tones you just heard, and it is not a model of correct Thai tone production. Deriving a tone from a mark and saying that tone correctly are separate skills, and this page and this app only really help with the first. For the second, a person who will correct you is the tool, and ThaiPod101’s video lessons at least put a human voice on the vowel.
Frequently asked questions
What are the four Thai tone marks called?
ไม้เอก (mai ek), ไม้โท (mai tho), ไม้ตรี (mai tri) and ไม้จัตวา (mai chattawa), which are simply “stroke one” through “stroke four”. English sources often call them the low, falling, high and rising tone marks, and those names are wrong often enough to mislead you, since the tone depends on the consonant underneath. Phayan uses the Thai names and teaches each mark attached to a consonant class; ThaiPod101 lists them with the English names, which is quicker to read and less accurate.
Does ไม้เอก always mean low tone?
No, and this is the single most useful correction on this page. ไม้เอก gives low tone on a mid-class or high-class initial and falling tone on a low-class one. ไม่ (mâi, not) is low-class ม with ไม้เอก and it is falling; ใหม่ (mài, new) is the same letter made high-class by a silent ห and it is low. Phayan drills the mark and the class together for this reason. An Anki deck of “mark equals tone” will teach you the wrong thing efficiently.
Where does a Thai tone mark go on the syllable?
Above the initial consonant, stacked on top of an above-vowel if one is already there, as in สี่ (sìi, four). In a cluster it is written over the second letter, and after a silent ห it is written over the letter that follows, but in both cases the tone is computed from the class of the first letter in the syllable. Phayan builds words letter by letter, so the mark is placed as its own step and the stacking becomes visible rather than decorative.
Why are ไม้ตรี and ไม้จัตวา so rare?
Because they are effectively mid-class only. A mid-class initial needs two extra marks to reach the high and rising tones; high-class and low-class letters get to those tones through their unmarked forms and through pairing with each other, so they never took the marks. You will still meet ไม้ตรี early in โต๊ะ (tó, table). Phayan introduces both inside words rather than as symbols to memorise, since drilling a mark you meet twice a month in isolation is wasted effort.
Do I need the tone marks to know how a word sounds?
You need them, and they are not sufficient on their own. A mark is one of three inputs; the consonant class and whether the syllable ends live or dead are the other two, and plenty of Thai syllables carry a tone with no mark at all. Phayan teaches the marks after finals and syllable types for that reason. Google Translate will read a word aloud for you without any of this, which answers one word and teaches you nothing about the next.
The marks are one input. For the table they feed into, see the Thai tone rules; for the classes that decide what each mark produces, Thai consonant classes; and for the third input, the one that decides whether a syllable is live or dead, long and short Thai vowels. If the five tones are not yet sounds to you rather than names, the five Thai tones with audio is the place to start.