Thai Final Consonants: 39 Letters, Eight Sounds
TL;DR: Thai has 42 letters in everyday use and 39 of them can close a syllable, but between them they make only eight sounds at the end of a word: -k, -ng, -t, -n, -p, -m, -w and -y. Eighteen different letters all come out as -t. A letter at the end of a syllable is therefore a much smaller problem than the same letter at the start, and which of the eight it is decides the tone.
Thirty-nine letters, eight endings
The first weeks of Thai are spent learning that a letter has a sound. Then you meet ปาก (bpàak, mouth) and the ก at the end behaves; you meet อาจ (àat, may) and the จ at the end does not. จ is a j at the front of a syllable. At the back it is a t. Nothing in the writing warns you.
This is the rule that fixes it, and it is the most generous rule in the script: a Thai syllable can only end in eight sounds. They are -k, -ng, -t, -n, -p, -m, -w and -y. Every one of the 39 letters that can sit at the end of a syllable makes one of those eight and nothing else. There is no aspiration at the end, no s, no ch, no l, no r. The letter keeps its shape and gives up its sound.
Three letters never close a syllable at all: อ, ห and ฮ. Add the two obsolete letters ฃ and ฅ, which you will see in an alphabet chart and nowhere else, and the arithmetic comes out at 39 finals from 42 letters in everyday use.
Which letters make which ending
The whole system fits in one table. The examples are ordinary words, not curiosities.
| Ending | How many letters | The letters | Example |
|---|---|---|---|
| -t | 18 | จ ฉ ช ซ ฌ ฎ ฏ ฐ ฑ ฒ ด ต ถ ท ธ ศ ษ ส | อาจ (àat, may) |
| -p | 7 | บ ป ผ ฝ พ ฟ ภ | ดับ (dàp, to extinguish) |
| -n | 6 | ญ ณ น ร ล ฬ | กัน (gan, together) |
| -k | 4 | ก ข ค ฆ | ปาก (bpàak, mouth) |
| -ng | 1 | ง | ถึง (tʉ̌ng, to arrive) |
| -m | 1 | ม | สาม (sǎam, three) |
| -w | 1 | ว | ข้าว (kâao, rice) |
| -y | 1 | ย | เคย (kəəi, used to) |
Phayan is an app for learning to read Thai script, and this table is a level rather than a reference page in it: L3, Finals and syllable types, sits inside the free part of the course. The progression is letter by letter from zero, every word carries audio, and the progress is kept in the browser without an account, so the first levels can be worked through before deciding anything.
Eighteen letters that all say -t
Look at the first row again. Eighteen of the 39 finals, nearly half of them, produce the same sound. จ ฉ ช ซ ฌ ฎ ฏ ฐ ฑ ฒ ด ต ถ ท ธ ศ ษ ส is not a group with anything in common at the front of a word: it holds three different s-letters, four different t-letters, a ch and a j. At the end of a word all eighteen stop the syllable with an unreleased t.
The three s-letters are the clearest case. ศ, ษ and ส give you three ways to write an s at the start of a syllable, which is a genuine nuisance to spell. At the end they collapse into one thing: เศษ (sèet, a remainder), พิษ (pít, poison), โทษ (tôot, punishment). The script front-loads its difficulty into the beginning of the syllable and gives the ending away almost free.
The practical consequence is worth stating plainly. You do not need to know which of the eighteen you are looking at in order to read the word. You need to recognise that it is one of them.
The ending is what decides the tone
This is why finals are taught before the tone table rather than after it. The eight endings split into two groups, and that split is one of the three inputs the tone of a syllable is derived from.
Five of them ring on: -n, -m, -ng, -w, -y. A syllable ending in one of those is live. Three of them stop the syllable dead: -k, -t, -p. A syllable ending in one of those is dead. กัน (gan, together) is live and holds the mid tone with no mark on it. กัด (gàt, to bite) is dead, with the same mid-class initial and no mark either, and it comes out low.
Nothing visible on the page distinguishes those two words except the last letter, so the last letter is doing the work. The full tone rules take the class of the initial, the length of the vowel and this live-dead split and give one answer; the long and short vowels are the other half of the same question, because a long vowel with no final is live too.
Reading the end of the word first
Thai text has no spaces between words, so the reader has to decide where each word stops. The eight endings are the strongest signal available for that, and they are worth using deliberately.
Take ตาล (dtaan, palm tree). The ล at the end is not an l. It is an -n, so the syllable is live, so the word can only be dtaan and cannot be dtaal, and the next character starts something new. The same reflex reads ศาล (sǎan, court), ควร (kuuan, should) and เหรียญ (rǐian, coin), where ล, ร and ญ all arrive at the same -n. Four letters, one ending, and no ambiguity about where any of the four words end.
It is worth noticing what this does to the size of the job. Learning the consonant classes means learning 42 individual facts. Learning the finals means learning eight, and a habit of looking at the last character before deciding what the word is.
Where this sits in learning to read
Finals arrive early in Phayan, in the level named for them, and they arrive attached to words rather than as a list: กัน and กิน as live syllables, กัด and ดับ and ปิด as dead ones, with the tone consequence introduced in the same round rather than saved for a table later. That order is deliberate. A learner who meets the live-dead split as an abstraction has to apply it; a learner who meets it as the difference between two words already knows it.
If you are starting from nothing, the sequence that works is the alphabet, then the vowels, then the finals, then the tone table, which is when everything before it starts paying.
Level 3 covers finals and syllable types and is part of the free course.
Frequently asked questions
What are the final consonants in Thai?
A Thai syllable can end in only eight sounds: -k, -ng, -t, -n, -p, -m, -w and -y, and 39 of the 42 letters in everyday use produce one of them. Eighteen different letters all end as -t, which is why the end of a word is far easier to read than the start of one. Phayan teaches the eight endings as a level of its own rather than as a spelling appendix, attached to words the learner can already decode.
How do I know what sound a Thai letter makes at the end of a word?
Find the letter in one of eight groups rather than trying to recall it individually. ก ข ค ฆ end as -k, the eighteen-letter group ending จ ฉ ช ซ ฌ ฎ ฏ ฐ ฑ ฒ ด ต ถ ท ธ ศ ษ ส ends as -t, บ ป ผ ฝ พ ฟ ภ ends as -p, ญ ณ น ร ล ฬ ends as -n, and ง ม ว ย each end as themselves. Phayan drills the grouping on real words, where Anki decks built from letter lists tend to drill the initial sound only and leave the final unlearned.
Is it safe to guess a Thai word from its ending alone?
The ending is reliable, the word is not. A final consonant genuinely only ever makes one of the eight sounds, so that part can be trusted completely, but two different words can share an ending and be told apart only by the tone and the vowel. Phayan puts the live-dead split next to the tone rule for that reason, so the ending is learned as an input to the tone rather than as an answer on its own.
What is the difference between a live syllable and a dead syllable?
A live syllable ends in a ringing sound, one of -n, -m, -ng, -w or -y, or in a long vowel with nothing after it. A dead syllable stops, either on -k, -t or -p, or on a short vowel with no final at all. The distinction exists because the tone of a syllable is derived partly from it, and Phayan introduces the two types in the same round as the first tone rule that depends on them. Transliteration-first courses such as Ling and ThaiPod101 rarely raise it, since it only becomes visible once the script is being read.
So the same letter is a different sound depending on where it is?
Yes, and it is one of the few places where Thai spelling makes life easier rather than harder. จ is a j at the front and a t at the back; ล is an l at the front and an -n at the back; ศ, ษ and ส are three separate s-letters at the front and one -t at the back. The set of endings is small and closed, so this is eight things to learn rather than 42, and Phayan puts them in the free part of the course for that reason.