The Thai script is a syllabic alphabet based on the Brahmi script adapted to write the Thai or Siamese language. Its invention is attributed to King Ramkhamhaeng, who reigned from 1275 to 1317. It is also possible that the Khmer alphabet might have had an influence on the Thai alphabet. The oldest Thai inscription dates from 1283.
The Thai script has some very complex rules on how letters are pronounced. Often multiple letters represent the same sound. This is partially due to the fact that many sounds found in Indian languages did not exist in the Thai language, so letters representing similar sounds in Indian languages came to represent the same sound in Thai, and also due to phonological changes in the Thai language in the past hundreds of years that have merged different sounds into the a single sound.
On the other hand, the sounds of many Thai letters differ depending on whether the letter occurs at the start or the end of a syllable. There are only six consonants that can end a syllable, namely /p/, /t/, /k/, /m/, /n/, and /ng/, but nearly all letters can occur at the end of a syllable (but pronounced as one of these six consonants).
The following is the basic Thai alphabet. Note that the sound the letter stands for at the beginning of a syllable is written as C-, where as the sounds at the end of the syllable is written as -C.
You might have noticed the blue letters L, M, and H, below the phonetic values of the letters (the text in red). These denote the "class" the letters belong to. Another peculiar characteristic of the Thai alphabet is that each letter is classified into one of three classes: low, middle, and high. We will revisit these classes later.
Like other Brahmi-derived scripts, a Thai letter used as the initial consonant of a syllable also carries the inherent vowel /ɔ/. When the letter occurs at the beginning of a consonant cluster or at the end of a syllable the inherent vowel is left unpronounced. However, unlike other related scripts which usually use a mark to indicate that the inherent vowel is not pronounced, Thai does not make use of this mark, so often it becomes somewhat confusing to the beginning learner as to which letter's inherent vowels should be pronounced and which shouldn't be. #>
In order to represent a different vowel other than the inherent, extra strokes or marks are added around the basic letter. They are illustrated in the following chart:
Not sure what some of the sounds stand for? Visit the Phonetics page for more details.
In addition to the typical Thai letters and vowel markers, loan words from Sanskrit and Pali (a South Asian language related to Sanskrit) employ four special letters and four special vowel markers.
Thai is a tonal language, meaning that in the pitch just as important to the correct pronunciation of the syllable as its sounds. There are five tones in Thai, low, middle, high, falling, and rising. To represent these tones, there are four tone marks in Thai, with the unmarked letter denoting the fifth tone. However, it is not as simple as it sounds. The real tone of a syllable is indicated by the tone mark combined with the class of the letter, conditioned by whether the syllable ends with a stop consonant and whether the vowel is short or long. It is best illustrated in the following grid.
The combinations with no tone mark might be a little bit confusing. First of all, the headings that include V and C denote the ending sequence of sounds of a syllable. VL represents a long vowel, VS means a short vowel, CN represents a nasal consonant (/m/, /n/, /ng/), and CS represents a stop consonant (/p/, /t/, /k/). Sounds placed inside parenthesis means that the sounds may or may not occur. For example the sequence -VL(CN) stands for syllables ending in VL (a long vowel), and VLCN (a long vowel followed by nasal consonant like /m/, /n/, or /ng/). Equivalently, the examples in Thai also reflect the sound sequence. The vowel markers on top of the black letter denote the long vowel /i:/ and the short vowel /i/. The greyed out letter means that the sound may or may not occur, and thus is equivalent to (CN).
There is no space or any kind of separator between words, so all the words in a sentence form one long block of letters. The only division, a space, occurs between sentences or phrases. The direction of writing, like other Brahmi-derived scripts, runs horizontally from left to right, and then downward when the horizontal space fills up.