One of the most interactive and theatrically sophisticated early English plays, the fifteenth-century Middle English morality play Mankind balances and complicates a conventional allegory of vice and virtue with a thematic emphasis on language. Associated with Lent and the pre-Lenten season of Carnival, it dramatizes a verbal battle waged for Mankind’s soul: it pits the stately, Latinate preaching of Mercy, who embodies Lent’s emphasis on penitence, confession, and piety, against the rhetorical tricks of the demon Titivillus and jokes, derision, and vulgarity from the four vices of worldly temptation, representing carnival themes of revelry, trickery, and social upheaval. Each side addresses the audience throughout the play, implicating them in their machinations for or against Mankind. Engaging with the late-medieval religious conflict between English-language Lollardy and a Catholic orthodoxy built on Latinate authority, Mankind demands that its audience distinguishes between virtuous and vicious uses of language, whether in Latin or English.