Who speaks these lines?

The one who spoke these lines is Mercutio. If you have read or watched Romeo and Juliet, you will be familiar with him. He is the one who has spoken these lines because he learned that a letter has been sent regarding challenging Romeo to a duel.

He is actually Romeo’s close friend and he is also the relative of Count Paris and Prince Escalus. His character is well-liked by a lot of people because he has a quick wit. He is able to show his cleverness through the way that he speaks. He is considered to be one of the most memorable characters that Shakespeare has ever created.