The peoples of Laos are divided by language, culture, and location. Lao officials distinguish four basic ethnolinguistic groups: the Lao-Lum, or valley Lao; the Lao-Tai, or tribal Tai; the Lao-Theung, better known as the Mon-Khmer; and the Lao-Soung, or Hmong and Man. Mountain people sometimes are called Kha (“Slaves”), a pejorative term. The Lao-Lum live in the lowlands, on the banks of the Mekong and its tributaries, and in the cities. They speak Laotian Tai, which is closer to the language spoken by the Thai of Thailand than it is to the language of the local Tai-speaking tribes. The Lao-Tai include such local groups as the Black Tai (Tai Dam) and Red Tai (Tai Deng), both names referring to the dress of the women; the Tai Neua, or Tai of the north; the Tai Phuan of Xiangkhoang province; and the Phu Tai. The Lao-Tai live throughout the country, chiefly in upland areas, and their various dialects are mutually intelligible.

Other distinct linguistic groups are few in number. Speakers of Tibeto-Burman dialects, who also came from southern China, live in the north and northwest. Chinese and Vietnamese live primarily in the urban areas. Initially, French was the language of the Lao elite and of the cities, but by the 1970s English had begun to displace it. Under the leadership of the Lao People's Revolutionary Party, Vietnamese has become the third language of the elite. Prior to the establishment of the Lao People's Democratic Republic (LPDR) in 1975, it was accurate to say that the Lao-Lum peoples had a distinct pattern of culture and dress. They also had a well-defined social structure, differentiating between royalty and commoners. The members of the elite included only a few outsiders who were not descendants of nobility. Most of the elite lived in the cities, drawing their incomes from rural land rents or from urban occupations. After 1975 a new elite emerged representing the victorious leftist forces. Many of this group, however, were of aristocratic origin.