Lao, sometimes referred to as Laotian (ລາວ 'Lao' or ພາສາລາວ 'Lao language') is a tonal language of the Tai–Kadai language family. It is the official language of Laos, and also spoken in the northeast of Thailand, where it is usually referred to as the Isan language.
The Lao language serves as an important lingua franca as the country of Laos consists of multiple ethnic groups, whose population speaks about 86 different languages.
Spoken Lao is mutually intelligible with the Thai language (the two languages are written with slightly different scripts but are linguistically similar).
Lao, like many languages in Laos, is written in the Lao script, an abugida. Although there is no official standard, the Vientiane dialect has become the de facto standard.