The roles language played in shaping and articulating one’s identity in Greco-Roman and Jewish antiquity constitute a backdrop against which the new developments attested in early Christianity can be measured. The ways in which foreign language speakers appeared in the Jewish Bible and Classical literature provided tropes, references, and allusions widely employed by early Christian authors. The chapter starts with an analysis of ancient Greek literary, historical, and philosophical compositions, from Homer to Aristotle, and investigates why the thought universe of the Classical Greek literati was virtually monolingual. It then proceeds to an overview of developments in the Hellenistic and early Roman eras and traces how the monolingual antiquity of Classical Greece gradually became the bilingual universe of the Roman empire, where Latin always shared its prestigious status as a vehicle of culture with Greek. The final section focuses on how early Jewish traditions depicted foreign languages and their speakers and how this culture adapted multilingual self-expression. In the conclusion, we discuss why language was rarely a decisive factor of group identity in these cultures and problematize the idea that the presence of linguistic differences by itself is a sufficient factor to trigger the processes of identity consolidation and objectification.