The investigation described in this paper was concerned with language alternation (code-switching) in the speech of Chicano migrant workers in Florida. In order to study Chicano bilingualsim, three principal sources were utilized: (1) a revised version of Wolck's sociolinguistic background questionnaire; (2) pictorial questionnaires such as Sapon's Pictorial Linguistic Interview Manual and pictures taken from newspapers, magazines, and the Sear's catalogue; and (3) relaxed conversational situations between bilinguals, taped by residents of the migrant camps. The specific purpose of the research was to observe the use of unassimilated loanwords which were phonologically English, but which were used in the Spanish of 33 informants. It was found that the vast majority of informants did not rely on direct English borrowings. If they borrowed any lexical items at all, they tended to assimilate them into their Spanish. They were aware of the linguistic norms of at least one of the two languages and they were sensitive to the separate identity of Spanish and English. Three sample conversations are presented, followed by an analysis of the various causes for the language switching in each. Educators should recognize the differences between Chicanos who switch from Spanish to English because they cannot distinguish the two languages, or from an inability to recall Spanish lexical items, and those who use language switching deliberately in order to convey additional affective meaning. The habit of the latter group should be recognized as an assertion of their dual cultural heritage. (CFM)