In Catalonia, Spain, speaking the Catalan language (as opposed to Castilian Spanish) habitually is an overt sign (Barth 1969) of Catalan identity. However, widespread bilingualism in Catalan and Castilian Spanish results in language mixing that blurs the boundaries between the two languages in speech. Therefore, it is standard written Catalan--the product of conscious efforts to distance the language from Castilian by the standardizers of the early 20th century--that becomes the clearest mark of the distinctness of a Catalan people. The difference between the Catalan written standard and Catalan as spoken by by habitual Catalan speakers and habitual Castilian speakers raises several questions for researchers concerned with the role of language ideologies in the imagination and performance of national identities. What ideologies of the relationship between the Catalan written standard and spoken Catalan exist among native and second-language speakers of Catalan? How do speakers' views of this relationship relate to their national loyalties? Exploring these questions through linguistic anthropology fieldwork in Barcelona, Spain will enable me to refine theories of the role of language standardization in the development and maintenance of national sentiment.