Romeo's use of language changes per scene depending on what Shakespeare is trying to portray about Romeo. For example, Romeo will use different kinds of language when he is exchanging witticisms with his friends, when he is conversing with Friar Laurence, and when he is portraying his amorous emotions. Below are a couple of examples with references to language devices Shakespeare uses to portray Romeo in different situations.
One example of witty language Romeo uses when he is with Mercutio and Benvolio can be seen in Act II, Scene IV. This scene takes place the morning after Romeo abandons his friends at the end of the Capulet Ball. His friends assume he has disappeared because he was pursuing Rosaline and that he was with her all night, which is why Mercutio begins his conversation with Romeo that morning by making all sorts of sexual innuendos. Romeo continues the bantering by adding a pun of his own that can also be interpreted as a sexual innuendo. Romeo tells Mercutio that his "pump [is] well-flower'd" (II.iv.59). The word "pump" literally refers to shoe. In those days, men wore decorations on their shoes, such as flowers. However, since this line follows a great deal of dialogue involving sexual innuendos, the word "pump" can also be translated as having more suggestive meaning, making the line another sexual innuendo. Aside from the linguistic device of puns, Shakespeare also has Romeo use a form of repetition called alliteration. Alliteration is when we repeat the first sound of many consecutive words. Alliteration can be seen with the repetition of the -s sound in Romeo's line, "O single-sold jest, solely singular for the singleness!" (63). This line follows the pun repartee Romeo starts concerning shoes, and shows how the linguistic device of repetition can add to the humor of the language.
For the romantic scenes, we see Shakespeare make Romeo use a lot of metaphors to portray amorous emotions. For example, when Romeo first sees Juliet, he uses many metaphors to speak of her beauty. One metaphor can be seen in the first line he uses to speak of her, "O, she doth teach the torches to burn bright!" (I.v.46). In this line, Romeo is comparing Juliet to a flaming torch, saying that she is even brighter than the torch. He even compares her to a "snowy dove trooping with crows," meaning a bright, white, beautiful bird walking around with dark, black, typical, even ugly birds (50).
Hence, Shakespeare uses many different language devices for Romeo, such as puns, repetition, and metaphors, to portray his different emotions, including both his humorous and amorous moods.