The tone of the prologue in Romeo and Juliet is somber and foreboding. It sets the stage for the tragic events that will unfold throughout the play. The prologue, delivered by the Chorus, provides a brief overview of the story, mentioning the feud between the Montague and Capulet families and the doomed love of Romeo and Juliet. The language used is formal and poetic, with a sense of inevitability and fate. The prologue prepares the audience for the themes of love, conflict, and tragedy that will dominate the play.