Hypothetical superfamily of North American Indian languages that unites a number of languages and language families mainly of the far western U.S. and Canada.
The Penutian hypothesis was proposed by Roland B. Dixon and Alfred L. Kroeber in 1913 and refined by Edward Sapir in 1921. Like the Hokan hypothesis (see Hokan languages ), it attempted to reduce the number of unrelated language families in one of the world's most linguistically diverse areas. At its core was a group of languages spoken along California's central coast and in the Central Valley , including Ohlone (Costanoan), Miwok, Wintuan, Maidu, and Yokuts. Sapir added Oregon Penutian (languages once spoken in eastern Oregon), Chinookan (spoken along the lower Columbia River), Plateau Penutian (languages of Plateau Indian peoples), Tsimshian (spoken in western British Columbia), and Mexican Penutian (spoken in southern Mexico). Aside from the Mexican group, all the languages are today either extinct or spoken almost exclusively by older adults. Though the hypothesis remains unproven, at least some languages of the group are probably related to each other.