Lao or
Laotian (, BGN/PCGN: phasa lao, ) 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. Being the primary language of the
Lao people, Lao is also an important second language for the multitude of ethnic groups in Laos and in Isan.