Lao is the official language of Laos (the Lao People's Democratic Republic) and belongs to the Tai-Kadai language family, the same family as Thai. The two languages are closely related — standard Thai and standard Lao are largely mutually intelligible in spoken form — though their writing systems differ. The Lao script, an abugida derived from ancient Khmer and ultimately Brahmic traditions, was developed around the 14th century during the Lan Xang Kingdom. Lao is a tonal language with six tones and is spoken natively by about half the population; the rest belong to dozens of distinct ethnic minority groups including the Khmu, Hmong, and various Tibeto-Burman peoples. French was the colonial language of administration under French Indochina (1893–1953) and left some traces in modern vocabulary. The Mekong River valley forms the cultural and linguistic heartland of Lao-speaking peoples.
