Wintu /wɪnˈtuː/ is a critically endangered Wintuan language spoken by the Wintu people of Northern California.It is the northernmost member of the Wintun family of languages.The Wintuan family of languages was spoken in the Sacramento River Valley and in adjacent areas up to the Carquinez Strait of San Francisco Bay.Wintun is a branch of the hypothetical Penutian language phylum or stock of languages of western North America, more closely related to four other families of Penutian languages spoken in California: Maiduan, Miwokan, Yokuts, and Costanoan.The Wintu were in contact also with adjacent speakers of Hokan languages such as Southeastern, Eastern, and Northeastern Pomo; Athabaskan languages such as Wailaki and Hupa; Yukian languages such as Yuki and Wappo; and other Penutian languages such as Miwok, Maidu, Yokuts, and Saclan.Besides these contiguous languages surrounding the Wintun area wider contacts with speakers of Russian, Spanish, and English.As of 2011, Headman Marc Franco of the Winnemem Wintu has been working with the Indigenous Language Institute on revitalization of the Winnemem Wintu language.