Alliteration can be seen when Mercutio says that last night Romeo gave them "[t]he slip, sir, the slip," meaning that Romeo disappeared, abandoning them at the Capulet's home (48). Alliteration is seen in the repetition of the consonant "s" sound.
We also see several puns in this exchange between Romeo and Mercutio. The first pun we see is a play on the word "courtesy." Romeo excuses himself for abandoning his friends, saying that, "[I]n such a case as mine a man may strain courtesy" (50). Mercutio, thinking that Romeo is still pining over Rosaline, turns the word courtesy into curtsy, saying that "such a case" as Romeo's "constrains a man to bow in the hams" (51-52). Since a curtsy is a woman's manner of bowing, Mercutio is asserting that Romeo's pining behavior is womanish.
Another pun is made from the word "pump" (59). When Romeo says, "Why, then is my pump well-flowered," he is referring to feminine decorations worn on shoes, "pump" referring to shoes. However, "pump" can also be a sexual innuendo, while "flower" can refer to maiden women.
Finally, more alliteration is seen in the repetition of the consonant "s" sound in "single sole," "solely singular," "single-sold," and "singleness" (60-63).