The Barcelonese author Juan Marsé has remarked of his 1990 novel, El amante bilingüe, that it is intended to represent the “schizophrenic” nature of Barcelona, referring to what Marsé views as the fundamental cultural and linguistic division of the officially bilingual city’s inhabitants into two national identities: Spanish-speaking “Castilians” and Catalan-speaking “Catalans”. The rhetoric of illness that Marsé uses to describe his novel suggests that the existence of more than one language and cultural identity in Barcelona, rather than a positive force, is actually pathological and can lead to mental illness in its inhabitants. In Marsé’s novel, the plight of the book’s protagonist, an individual who functions in both spheres of Barcelonese society while fully identifying with neither, supports the theory that bilingualism and biculturalism may lead to self-destruction. Forced to choose between his two “identities”, Marsé’s main character irreparably splits himself into two irreconcilable psychological entities: the Catalan Juan/Joan Marés and the Spanish Juan Faneca. Marsé’s novel thus emphasizes the dichotomic nature of Barcelonese society, in which one is forced to choose between two diametrically opposed cultural and linguistic affiliations: one is either Catalan or Castilian, and no allowance is made for an intermediate or dual identity. This paper explores the rhetorical tools Marsé uses to depict the binarism of Catalan society and the adverse effects this “split personality” can have on its inhabitants as well as examining the questions it raises about the possibilities (or lack thereof) for national identity in contemporary Barcelona.