Thai tone marks

Thai has four tone marks, written above the consonant. They are shown here on ก so you can see where they sit. The trap is that a tone mark does not name a tone. ไม้เอก mái èek does not mean low tone. What the mark produces depends on the class of the consonant it sits on, so the same mark gives a different result on a middle, high or low class letter. ไม่ and แต่ both carry ไม้เอก. The first is mâi, falling, because ม is low class. The second is dtàe, low, because ต is middle. Same mark, two different tones, and nothing on the page announces the difference. The first table below gives every combination, with a word for each. The names of the marks are the number words. เอก èek, โท thoo, ตรี dtrii and จัตวา jàt-dtà-waa are one, two, three and four, the same words that rank a bachelor's degree, a master's and a doctorate as ปริญญาตรี bpà-rin-yaa-dtrii, ปริญญาโท bpà-rin-yaa-thoo and ปริญญาเอก bpà-rin-yaa-èek. On a middle-class consonant the numbers line up exactly, and so do the names: mái èek gives เสียงเอก sǐang èek, the low tone; mái thoo gives เสียงโท sǐang thoo, falling; mái dtrii gives เสียงตรี sǐang dtrii, high; mái jàt-dtà-waa gives เสียงจัตวา sǐang jàt-dtà-waa, rising. The mark and the tone it produces carry the same name, which is the whole reason the mark looks like it is announcing the answer. A middle-class live syllable with no mark takes the one tone that has no number, สามัญ sǎa-man, mid. That shared naming is why the mark looks like it is announcing the answer, and it is also why it misleads. It breaks on one class only: on a high-class letter the first two marks still give the tones their names promise — ถ่าย thàai is low, ข้าว khâao is falling. It is the low class that turns the naming inside out. ไม้ตรี and ไม้จัตวา are rare because the rest of the system already writes what they would say. A low-class initial reaches falling with mái èek and high with mái thoo. For the rest it depends on the letter: the paired letters borrow their high-class partner — ค่า khâa against ข่า khàa — and the ten unpaired low letters take a silent ห in front, which puts the whole syllable on the high-class row, marks included. That is why หน้า is nâa, falling, and หน่อย is nàwy, low, and not the high náa and falling nâwy that น alone would give. A high-class initial is already rising when it is unmarked in a live syllable, and reaches low and falling with the first two marks. That leaves only middle-class consonants without a way to write high and rising, and that is the job these two marks do. In practice you will almost only meet them sitting on a middle-class letter. You will still meet them: they turn up on loanwords, on menus and shopfronts, and in a small set of very ordinary words — โต๊ะ, ก๊อก, ตุ๊กตุ๊ก, เดี๋ยว, ก๋วยเตี๋ยว. A written mark settles the tone on its own. Once it is there, live or dead and the length of the vowel stop counting — โต๊ะ dtó is a dead syllable with a short vowel and is still high, ล่ะ is lâ, จ๋ะ is jǎ. Those things only decide the tone when no mark is written. Plenty of words carry no mark at all and still have a tone, because an unmarked syllable takes its tone from the class of the initial, from whether the syllable is live or dead, and from the length of the vowel. The grid is set out on the Thai tone rules, where it belongs: seven outcomes, three for a low-class initial and two each for middle and high. The one worth carrying here is the low-class row, because it is the row a mark most often overrides — มา maa, นก nók, มาก mâak. Those seven cover almost every unmarked syllable, and two things sit outside them. A short list of very common words is irregular and has to be learned as it is: ก็ is said gâw, though nothing in the spelling says so. And in a two-syllable word with an unwritten vowel the class of the first consonant carries over to the second, so ขนม is khà-nǒm, rising, from the high-class ข and not the low-class น. You can read a whole sentence without meeting a single tone mark, and every syllable in it still has a tone. Read the syllable in a fixed order, consciously, until it is quick. Find the initial consonant. Name its class. Look for a mark above it. Then read the row. Take ข้าว: the initial is ข, high class; the mark is ไม้โท mái thoo; high class with mái thoo gives falling; the mark settles it, so the long vowel and the live ending change nothing. khâao. Now take หน่อย: the first letter is ห, but here it is silent and its only job is to put the syllable on the high-class row; the mark ไม้เอก mái èek sits on น, the letter you actually say; high class with mái èek gives low. nàwy — not the falling nâwy that น on its own would give. That is why the classes come first. Learn the class, then the mark, and the rules stop looking arbitrary. The three classes and the letters in each are set out at Thai consonant classes, which also carries the eight ห combinations and the closed list of four words that a silent อ leads in the same way — อยาก yàak, อยู่ yùu, อย่า yàa and อย่าง yàang. The live and dead distinction, and the full derivation in one table, are at the Thai tone rules.