This dissertation examines the social process of language study abroad in a multilingual West African setting, paying attention to how language learners mobilize multiple linguistic resources to navigate the superdiverse linguistic landscape and the ideologies that drive their practices. Study abroad is generally believed to be an ideal space for foreign language learning, but this view tends to assume a monolingual target language community. Most study abroad programs, in reality, take place in contexts of multilingualism which present learners with complex social, cultural and linguistic experience in terms of the contents and the manner by which they engage with the people while abroad. Through analysis of ethnographic research conducted during a summer-long Yoruba language study abroad program for U.S. learners of Yoruba in Southwest, Nigeria, I explore the language ideologies at play in various interactional settings and their effects on student learning. My analysis, which draws from Critical Applied Linguistics, demonstrates that study abroad in this context constituted a site for enforcing an idealistic, monolingual linguistic practices on learners; contrary to the linguistic and cultural realities, as well as learners' experience in the region. Through Critical Discourse Analysis of interactive practices by learners in the various domains of interaction, I show how the multilingual practices of learners and of the native speakers with whom the students interacted conflicted with the focus on monolingualism in the program's official ideology. Highlighting the multilingualism of a study abroad site, which is often left out in discourses about language study abroad, I thereby argue that multilingualism is not only the norm but actually inevitable in study abroad sites. Language study abroad programs should develop and promote programs that embrace this reality. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]