The Kitsai (also Kichai) language is an extinct member of the Caddoan language family.^[2] The French first record the Kichai people's presence along the upper Red River in 1701.^[3] By the 1840s Kitsai was spoken in southern Oklahoma, but by the 1930s no native speakers remained. It is thought to be most closely related to Pawnee.^[4][5] The Kichai people today are enrolled in the Wichita and Affiliated Tribes (Wichita, Keechi), Waco and Tawakonie), headquartered in Anadarko, Oklahoma.

Kitsai is documented in the still mostly-unpublished field notes of anthropologist Alexander Lesser, of Hofstra University. Lesser discovered five speakers of Kitsai in 1928 and 1929, none of whom spoke English. Communicating to the Kitsai speakers through Wichita/English bilingual translators, he filled 41 notebooks with Kitsai material.^[7]

Kai Kai was the last fluent speaker of Kitsai. She was born around 1849 and lived eight miles north of Anadarko. Kai Kai worked with Lesser to record vocabulary and oral history and prepare a grammar of the language.^[8]

In the 1960s, Lesser shared his materials with Salvador Bucca of the Universidad Nacional de Buenos Aires, and they published scholarly articles on Kitsai.^[7]

Some Kitsai words include the following:^[9]