They formed important settlements at various points on the Mekong, notably Luang Prabang, Wieng Chan (Vien-Tiane) Ubon and Bassac; and, heading inland as far as Korat on the one side and the Annamite watershed in the east, they drove out the less civilized Kha peoples, and even the Cambodians, as the Lao Pong Dam did on the west.
In eastern Siam the only towns of importance are Korat and Ubon, capitals of divisions, and Nong Kai, an ancient place on the Mekong river.
It is spoken throughout central Siam, in all parts of southern Siam except Patani Monton, in northern Siam along the river-banks as far up as Utaradit and Raheng, and in eastern Siam as far as the confines of the Korat Monton.