This dissertation investigates lexical borrowing in Spanish in New York. English-origin lexical material was extracted from a stratified sample of 146 Spanish-speaking informants of different ages, national origins, classes, etc., living in New York City. ANOVAs and Pearson correlations determined whether lexical borrowing frequency and the type of vocabulary used (i.e. idiosyncratic and shared) were correlated with speaker traits. Results show that all speakers, regardless of their English proficiency or how long they have been in the U.S., borrow. However, borrowing frequency is best predicted by immigrant generation. Furthermore, borrowing rate may play a distinct role for first and second generation Spanish speakers. In the first generation, the middle class, those with more education, better proficiency in English and more Spanish confidence borrow most often. In the second generation, Puerto Ricans and those with more English confidence borrow most. Results for borrowing vocabulary suggest that the middle class is more responsible for introducing novel vocabulary to the Spanish-speaking community than the working class. Overall, though, both novel and shared vocabulary are integral components of speakers' borrowing inventories. Finally, this dissertation examines flagging (e.g. pauses, fillers, metalinguistic commentary) near other-language strings to determine whether flagging is indicative of language awareness or linguistic disfluency. Results showed no support for the latter; but evidence for the former interpretation suggests that a simultaneous, albeit slight, process of deborrowing accompanies lexical borrowing in New York. The findings and the methodology of this dissertation contribute to several fields of language study. First, the definition of lexical borrowing used makes it germane to studying borrowing in situations of on-going, face-to-face contact in multidialectal communities. Furthermore, a corpus-based approach to differentiating between two types of bilingual speech phenomena, lexical borrowing and codeswitching, is offered. Second, findings show that borrowing in New York is not a 'deficit' behavior and that some aspects of identity (such as arrival age and class) cross-cut traditional (i.e. regional) characterizations of U.S. Latinos. Finally, findings for bilingual speech partially corroborate models describing the long-term outcomes of contact that predict that the quantity of contact features observable in a language is a function of the intensity of contact.