Most medieval morality plays tend, like the N-Town cycle and unlike the Wakefield cycle, to set up a dialectic between a relatively formal, Latinate dialect for God and other holy speakers and a colloquial, sometimes obscene or nonsensical, vernacular dialect for the figure of the Vice and his counterparts. Latin, whether quoted directly, or visible through a highly elevated English derived from Latin roots, usually gives holy sanction to the words of those who speak it. The final section of The Castle of Perseverance is a clear case in point. The speech of the four daughters of God is sprinkled with Latin, increasingly located at the end of the stanza as the action moves towards its climax. The speech of God the Father, though plain in its English, also highlights the beginnings and endings of some stanzas with Latin, and ends with the final exhortation, ‘Te Deum laudamus’ (line 3649). Latin becomes more insistent and more dominant as good triumphs over evil and salvation is affirmed.

Latin, in these plays as elsewhere, is also the language of the clergy, God's representatives on earth. Despite the strong presence of anticlerical satire in fourteenth-century non-dramatic literature, morality plays as a genre tend not to show unworthy clerics until the Reformation creates two churches and two contesting clergies, by which time the genre has arguably been hijacked into something different anyway.