Hopi (Hopi: Hopílavayi) is a Uto-Aztecan language spoken by the Hopi people (a Pueblo group) of northeastern Arizona, USA, although today some Hopi are monolingual English speakers.The use of the language has gradually declined over the course of the 20th century. In 1990, it was estimated that more than 5,000 people could speak Hopi as a native language (approximately 75% of the population); at least 40 of them were monolingual in Hopi.