This article argues that nonsense words in Twelfth Night and other early modern English comedies can help us think more clearly about our attempts to explicate difficult language in historical contexts. Focusing in particular on Sir Toby's untranslatable exclamation ‘Castiliano Vulgo’ and other meaningless foreign‐sounding phrases in a range of plays, the article discusses the social ramifications of miscomprehension or false interpretations, both for imagined characters on stage, and for scholars, editors, teachers, students, and audience members. How does our desire to eliminate confusion in our encounter with historical literature shape our responses to comic texts? Can we imagine a classroom or a Shakespearean theatre in which baffling, incomprehensible nonsense is a productive presence?