Before the 1960s, the people of Thai Isaan were simply labeled Lao and wrote in the Lao alphabet before the central government forcibly introduced the Thai alphabet and language in schools.
Most Isaan people now speak the Isan language which is closely related to the Lao language. The number of speakers of Isan has been estimated at between 15 million and 23 million, the majority of these being in Isaan. Most of these also speak standard Thai, generally more fluently the younger they are.
The Khorat dialect, spoken by around 400,000 people, occupies a linguistic position somewhere between Isan and standard Thai.
Although there is no tradition of written literature in the Isan language, in the latter half of the 20th century the region produced several notable writers, such as Khamsing Srinawk (who writes in Thai) and Pira Sudham (who writes in English).
There is a substantial Khmer minority, concentrated in the southern provinces of the Isaan.