Version 4 - August 8th, 2015, Latest update March 20th, 2017
The tones in writing
You will find the tones of the Thai language in the Thai writing, but you will have to learn the rules, I must admit, a bit tricky, but if you take it step by step, you will grasp it. If you try to hard you will get dizzy, so one step at the time, and I will do my best to introduce it that way.
One explanation to the great number of letters in the Thai alphabet is that they are used to describe tones. There are several letters for T och several for K and several for S, etc. So the particular K you choose as initial K actually decides what tone the whole word will have. All Thai consonants belong to three classes in this respect - to regulate the tone.
ขา and คา are both pronounced k-ah but have different tones.
In the representation of the alphabet below some of the consonants are coloured red. When a word is started off by one of these consonants and ends either by a long vowel or by a long vowel with a consonant that is not prounounced as p, t or k, you shall pronounce the word with a rising tone.
ขา k-ah "leg" ถาม t-ah-m "to ask"
Words beginning with any of the black consonants in the same position, i.e. followed by a long vowel or a long vowel and a consonant that is not pronounced p, t or k, will have an even neutral tone, neither high nor low.
คา k-aa "to be stuck " วาง w-aa-ng "to put"
The Thai Consonant Alphabet and class belongings illustrated by colour
ก ข ค ง จ ฉ ช ซ g-k-k-ng- j-ch-ch-s ด ต ถ ท ธ น บ ป ผ ฝ พ ฟ d-dt-t-t-t- n-b-bp- p-f- p-f ภ ม ย ร ล ว ศ ษ ส ห อ p-m-y- r-l-w- s-s-s- h-aw
Rising tone :
Red + long vowel (+m/n/ng) ---> rising tone
Black + long vowel (+m/n/ng) ---> neutral tone
Put some effort into assuring that your neutral tones really are steady and do not slide away in any direction. Being a Swede I have some experience in tone sliding :)
In conlusion Thai tones are described by three factors, the initial consonant, which vowel the word has, and how the word is ended. In help we will also have a couple of tone indicating signs that look like 1 and 2.
Relax, even though the system has been described as if you would have a huge amount of possibilities, this is by now means true. Actually the system must have been built up in order to save as much energy as possible in writing. I would say, this is a typical Thai feature, to find simple and real good solutions to complicated problems. The classes are similar in most respects and most rules apply for two classes while the third has its own rule.