My dissertation project deals with the use of the Arabic language and its perceived socio-cultural status in Spain during the sixteenth century, with a particular focus on translators of Castilian and Arabic. I focus on the language ideologies, social and professional strategies, and cultural practices of bilingual individuals who were employed as language workers (translators, negotiators, and other intermediaries) by the Spanish monarchy. I argue that the discourses around what could and should be "Spanish" languages centered around the use and status of Arabic. Arabic also functioned as an international link between Spanish humanists and other early European orientalists, and as a language of information and diplomacy for Spanish agents in North Africa and the Mediterranean. Despite hostile policies in the sixteenth century and ambivalent language ideologies thereafter, however, knowledge of Arabic and interest in the language was never extinguished and was in fact cultivated and rewarded within the Spanish monarchy under all of the Habsburg monarchs. In particular, I explore the ways in which bilingualism was used or resulted in the continual revision of a series of ideological boundaries between ethnic groups, religious communities, professional occupations, and even social classes. Rather than aiding in assimilation, acculturation, or even communication, I argue that the practice of employing bilingual intermediaries in the royal administration ultimately strengthened an exclusive and monolithic Spanish identity and concept of citizenship in the early modern period.