Kitanemuk was a Northern Uto-Aztecan language of the Serran branch. It was very closely related to Serrano, and may have been a dialect. It was spoken in the San Gabriel Mountains and foothill environs of Southern California. The last speakers lived some time in the 1940s, though the last fieldwork was carried out in 1937. J. P. Harrington took copious notes in the 1916 and 1917, however, which has allowed for a fairly detailed knowledge of the language.