The official national language, spoken by almost 100 per cent of the population is, THAI, classified by linguists as belonging to a Chinese-Thai branch of the Sino-Tibetan family.
Thai is one of the oldest languages in East and South-East Asia. Thai is a tone language of sino-tibetan origin. This means that differences in tone make differences in meaning. The Thai language has five tones (high, mid, low, rising, and falling tone), and if you mispronounce you do not simply say an incorrect word, you say another word entirely! Many Thais, however, (not all, of course!) speak some English and at least in the tourist areas of Thailand, like Bangkok, Phuket, or Ko Samui you can manage easily even without knowing Thai (in the more remote areas, like the Northeast, or the South, you might run into problems.)
The Thai language originally is monosyllabic in its formation of words. It is a characteristic to be found also in Chinese and, more or less, in other languages of Southeast Asia. Each word is complete in itself and admits no modifications as do inflectional languages with their differences of case, gender, number, etc.
King Ramkhamhaeng the Great who ruled the Sukhothai Kingdom from 1279-1298 initiated the Thai inscription in 1292. The inscription is considered to be a seminal source of Sukhothai history as well as a masterpiece of Thai literature.
Thai uses a script-like amalgamation of some 48 consonants and 32 vowels – more or less, depending on who’s counting. Different letters may be used to represent largely the same sounds. Worse, entirely too many Thai consonants resemble either snakes or squiggly-tailed pigs as viewed from behind, so merely noticing that “this is the letter that looks like a squiggly-tailed pig” will not help you read Thai.
There are no plurals in Thailand language, nor are there tenses as such. A word or two is usually added to determine the past, present or future.
Cornelius B. Bradley stated in Some Features of the Siamese Speech and Writing, published 1923, that Thai “words are symbols of concept per se, being wholly devoid of inflectional apparatus to express and define their relations with other words in the sentence. They are, therefore, free to function in any syntactical relation not incompatible with their essential meaning”.
Indeed, the Thai language has one of the simplest grammars of all languages, and many writers have claimed there is no grammar at all. However, in the judgement of Phaya Anuman Rajadhon, Thai has in the course of its historical and cultural development suffered at the hands of Thai grammarians who have introduced exotic rules and restrictions based on English, Sanskrit or Pali grammar.