Thai, also known as Siamese or Central Thai, is the national and official language of Thailand and the native language of the Thai people and the vast majority of Thai Chinese. Thai is a member of the Tai group of the Tai–Kadai language family. Over half of the words in Thai are borrowed from Pali, Sanskrit and Old Khmer. It is a tonal and analytic language. Thai also has a complex orthography and relational markers. Spoken Thai is mutually intelligible with Laotian; the two languages are written with slightly different scripts, but are linguistically similar.

Source: Wiki