The Okwanuchu language was spoken at the head of the Sacramento River and to the east on the upper McCloud River. Our only information about this language comes from fewer than 100 words recorded early in the twentieth century.
Okwanuchu is a member of the Shastan language family, the other members of which are Konomihu, New River Shasta, and Shasta. Together the Shastan languages comprise one branch of the hypothesized Hokan language family. This includes, in addition, Chimariko, Esselen, Karuk, the Palaihnihan languages (Achumawi and Atsugewi), the Pomoan languages (Central Pomo, Eastern Pomo, Kashaya, Northeastern Pomo, Northern Pomo, Southeastern Pomo, and Southern Pomo), Salinan, Washo, Yana, and the Yuman languages (Cocopa, Kiliwa, Kumeyaay, Maricopa, Mojave, Pai, Paipai, and Quechan).