Language techniques are literary terms that specifically define the way an author uses language to express meaning and illustrate a point. There are definitely many different language techniques to become familiar with, and Shakespeare certainly uses many of them. Two categories of language techniques are figurative language and rhetorical schemes. We can spot many language techniques by looking at the first scene alone.
The use of puns is one example of figurative language. Puns happen when we use a word that sounds exactly like another word that has a different meaning. The two Capulet servants use many puns in their opening lines. For example, Sampson uses the word "choler," meaning angry to argue that if they should be angered by the Montagues, they'll draw their swords. But in reply, Gregory turns "choler" into "collar," saying that should he draw his sword, he'll also need to draw his neck out of the hangman's collar, meaning noose (eNotes, I.i.3-4).
Parallelism is also a type of rhetorical scheme and language technique Shakespeare frequently uses. We can find a lot of parallelism in Prince Escalus's important speech in the first scene. For example, he opens the speech with what we can call tricolon parallelism. Tricolon parallelism happens when we have three parallel clauses within a sentence. Dr. Wheeler gives us the example, "That government of the people, by the people, and for the people shall not parish from the earth" (Wheeler, "Rhetorical Schemes"). The same tricolon parallelism can be found in Prince Escalus's lines:
Rebellious subjects, enemies to peace,
Profaners of this neighbour-stained steel--
Will they not hear? (77-79)
In these lines, Escalus is using three different ways to address those who were fighting in the street, and since each phrase of address similarly refer to the feuding citizens, we see that each phrase is parallel in meaning. Plus, since there are three parallel phrases, we also know that this is tricolon parallelism.