Within Thailand, there are four major dialects. The four primary dialects of Thai are not are not considered a different language. Rather, they are the regional form of Thai that is spoken by the locals, each with their distinctive pronunciations, phrases and words. All of the dialects are forms of the standard Thai language.
These dialects correspond with the four major regions of the country: the southern, the northern (“Yuan”), northeastern (“Isaan”), and central regions. There are a few minor Thai dialects such as Phuan and Lue, spoken by small populations. Official or Standard Thai is based on the idealized speech of the educated people of Bangkok and Central Plains. Northern Thai is spoken around Chiangmai and Chiangrai. Northesatern Thai is spoken to the east of Korat. Southern Thai is spoken south of Chumpon and to the Malaysian border.
There are different types of Thai “language” used by Thais in different social circumstances. For example, certain words or patterns of speech are used only by Thai royalty – called the royal language. There are also languages used for religious figures, polite everyday interactions and gruff or crude communications. The younger, education populations of the Northern, Southern, and Northeastern regions are bi-dialectal since they receive schooling in Standard Thai. However, in their homes and communities they maintain their regional identities and the local dialects are kept alive. Standard Thai is the language that is used when speaking with non-locals and aids in the ability of the peoples from different regions to communicate with each other.