Language serves as a formidable tool in Richard III, especially as a means of vengeance. Predictions and curses are pronounced and eventually come true. Promises that are made but subsequently broken lead to calamity. Indeed, curses, prophecies, and deceptive or reckless vows occur so often and with such intensity in Richard III that they significantly influence the play's conclusion.

As early as Act I, scene iii, Margaret impacts the narrative by cursing nearly every major character in the play. She wishes for the demise of King Edward and his descendants and a life of suffering for Queen Elizabeth. She curses Hastings and Rivers with premature death and condemns Richard to sleeplessness and downfall. She concludes by foretelling that Buckingham will be betrayed by Richard: "O Buckingham, take heed of yonder dog!/ Look when he fawns, he bites; and when he bites/ His venom tooth will rankle to the death." By the play's conclusion, nearly all of Margaret's predictions and curses have been realized.

Ironically, several characters doom themselves by reinforcing Margaret's curses with their own false promises and self-imposed curses. For instance, in Act IV, scene iv, Richard assures Queen Elizabeth that he loves her daughter, backing this claim with a self-curse meant to activate if his vow is untrue: "God and fortune, bar me happy hours!/ Day, yield me not thy light, nor, night, thy rest!" Richard's promise is indeed a lie; his real intention is to marry her daughter to strengthen his authority. His self-curse—misfortune and insomnia—mirrors Margaret's curse from Act I, and by the play's end, it comes to fruition.