Thai literature is the literature of the Thai people, almost exclusively written in the Thai language (although different scripts other than Thai may be used). Most of imaginative literary works in Thai, before the 19th century, were composed in poetry. Prose was reserved for historical records, chronicles, and legal documents. Consequently, the poetical forms in the Thai language are both numerous and highly developed. The corpus of Thailand's pre-modern poetic works is large. Thus, although many literary works were lost with the sack of Ayutthaya in 1767, Thailand still possesses a large number of epic poems or long poetic tales —some with original stories and some with stories drawn from foreign sources. There is thus a sharp contrast between the Thai literary tradition and that of other East Asian literary traditions, such as Chinese and Japanese, where long poetic tales are rare and epic poems are almost non-existent. The Thai classical literature exerted a considerable influence on the literature of neighboring countries in mainland Southeast Asia, especially Cambodia and Burma.
As speakers of the tai language family, the Siamese share literary origins with other Tai speakers in mainland Southeast Asia. It is possible that the early literature of the Thai people may have been written in Chinese.
However, no historical record of the Siamese thus far refers to these earlier literature. The Thai poetical tradition was originally based on indigenous poetical forms such as rai (ร่าย), khlong (โคลง), kap (กาพย์), and klon (กลอน). Some of these poetical forms—notably Khlong - have been shared between the speakers of tai languages since ancient time (before the emergence of Siam). An early representative work of Khlong poetry is the epic poem Thao Hung Thao Cheuang, a shared epic story, about a noble warrior of a Khom race in mainland Southeast Asia.
Indosphere and Sanskritisation
Through Buddhism's and Hindu's influence, a variety of Chanda prosodic meters were received via Ceylon.