Okanagan, or Colville-Okanagan, is a Salish language which arose among the indigenous peoples of the southern Interior Plateau region based primarily in the Okanagan River Basin and the Columbia River Basin in pre-colonial times in Canada and the United States. Following British, American, and Canadian colonization during the 1800s and the subsequent repression of all Salishan languages, the use of Colville-Okanagan declined drastically.