According to Haruo Aoki (1998), the Cayuse called themselves ""Liksiyu"" in their language. Their name "Cayuse" was derived from the French word "cailloux," meaning stones or rocks, adopted by early French Canadian trappers of the area. The name may have referred to the rocky area the tribe inhabited or it may have been an imprecise rendering of the name they called themselves. The tribe has been closely associated with the neighboring Nez Percé and Walla Walla. The Cayuse language is an isolate, independent of the neighboring Sahaptin-speaking peoples. The Cayuse population was about 500 in the eighteenth century.