Lao or Laotian /ˈlaʊʃən/[3] (ພາສາລາວ, BGN/PCGN: phasa lao, IPA: [pʰáːsǎː láːw]) 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