This chapter concentrates on how linguistic treatises of the first half of the 1500s, which all seem to be directly influenced by Dante's treatise on rhetoric and poetic style De vulgari eloquentia, linked multilingualism and its features across the peninsula to regional identities. The technical and rhetorical nature of linguistic performance is emphasized: speaking is a form of acting, whether on stage or in conversation at court. The chapter shows that the performative aspects of languages are examined in linguistic treatises. Indeed, through discussing rhetorical aspects such as pronunciation, intonation, inflection of voice, facial expressions, and gestures in different contexts. Concentrating on literary genres destined for oral performance such as comedy, these texts point out a sense of the potential ridiculous effect produced by an incorrect usage of language either on stage or in conversation in select social environments. Characters in Renaissance comedies, displayed a variety of languages that greatly contributed to the definition of characters' regional and social identity.