The Ofo language was a language spoken by the Mosopelea tribe who lived until c. 1673 in what is now Ohio along the Ohio River. They moved down the Mississippi River to Mississippi, near the Natchez people, and thence to Louisiana, settling near the Tunica. It was sometimes suspected that the Ofo language was Muskogean. But in 1908, anthropologist John R. Swanton discovered an aged female speaker living among the Tunica who had spoken Ofo since childhood. He obtained a vocabulary of the language, and quickly established that it was in fact Siouan, and similar to Biloxi.