This work is an attempt to synthesize the findings of the multi-disciplinary research on various aspects of Chicanos' use of their two languages, Spanish and English. After an introduction on notions of language, speech, and sociology, the text covers nine aspects of the question: (1) historical background on the relations between the English and Spanish languages and their speakers; (2) Chicano multilingualism and polyglossia; (3) an analysis of the speech situation, including the relevant psychological and social factors involved in language mixture; (4) a sociolinguistic analysis of Chicano Spanish; (5) a discussion of available analyses of Chicano English; (6) the private domain of language use, with particular attention to the relationships among language structure, language use, and the immediate social settings in which the act of communication takes place; (7) the public domain, that is, the use of language outside the circle of family and friends; (8) attitudes toward English, Spanish, and mixing; and (9) social and linguistic change among Chicanos. (AMH)