Another important purpose of the puns is to have the audience see the skillful...
As other’s have suggested, one important purpose of puns in Shakespeare's Romeo and Juliet is to lighten the mood so that the audience remains entertained throughout the play despite the tragic ending they know is coming.
Another important purpose of the puns is to have the audience see the skillful way in which Shakespeare plays with words. He shows off both his ability to craft an interesting story and his creativity with language and words. This also keeps the audience's interest as people listen for the different word games included in the dialog.
Shakespeare often used homonyms, or words that have the same sound but different meanings, to play with words. For example, Mercutio wants Romeo to dance at the Capulet’s party. However, Romeo’s heart is heavy because his beloved (not Juliet yet, but Rosaline) does not return his love. He declines to dance, saying:
"You have dancing shoes
With nimble soles. I have a soul of lead
So stakes me to the ground I cannot move."
Romeo is depressed because of his unrequited love for Rosaline. Shakespeare makes use of the similarity of “sole” and “soul” to explain why Romeo cannot dance. These kind of wordplays held audience member’s attention and also impressed Shakespeare’s chief patron, Queen Elizabeth, who was extremely well-educated and also a bit bawdy herself.
It is also important to bear in mind that audiences for Shakespeare’s plays in Elizabethan England did not sit quietly and listen to the words as modern audiences do. They often participated, applauding as the performance was going on when they liked the events or throwing things at the performers when they did not.
According to A Brief History of the Audience,
“Elizabethan audiences did not know what it meant to be quiet for a performance and would talk back to the actors.”
Thus, incorporating word play in the dialog is another device to keep the audience focused on the words, keep them amused, and elicit their attention to catch all the plays on words.
Tybalt accuses Mercutio of consorting—or associating—with Romeo. Shakespeare uses another play on homonyms that the Elizabethan audience would have understood. Consort could refer to Mercutio’s friendship with Romeo and it could also refer to a consort (group) of musical elements, as in the consort music that was popular at the time. Mercutio’s response to Tybalt illustrates the double entendre.
“Consort? What, does thou make us minstrels? As thou make minstrels of us, Look to hear nothing but discords.”
Shakespeare is showing the two possible uses of the word “consort” and also incorporating the word “cord” as “discord” to play on the theme of music. Mercutio is saying if you make minstrels of us, you will only hear poorly played cords and you will get discord—or a fight or disagreement—back.