Letters and love poetry circulate throughout Twelfth Night as the play reflects on the value and hidden dangers of written words. Shakespeare exposes the way poetry can lose all meaning and credibility when it follows formulaic patterns. There are plenty of self-conscious moments where Shakespeare reminds us of his position as a writer, especially when he draws our attention to the follies of conventional poetry even as he participates in the tradition. Yet, at various moments, Twelfth Night reminds us that, when verse is composed spontaneously and sincerely, poetry can have more power over human beings than anything else. Letters, too, can be both deceptive and freeing, depending on the writer. Even when words are "corrupted" by figures like Feste, they very often prove to be the best tools for revealing truth and wisdom.
Even though Twelfth Night warns against the dangers of written language, it also suggests that language has the power to reveal the truth.
Several characters in Twelfth Night compose and recite love poetry, which gives the play an opportunity to comment on the conventions of romantic verse.