What literary devices do the sane people in Hamlet use?

Let’s begin by assuming that there are some sane characters in Hamlet.  Loosely considering it, we could probably include all characters except Hamlet and Ophelia.  Shakespeare does employ a number of devices through the characters, from your basic literary techniques to more creative rhetorical devices. 

Polonius sets up a fake coincidence when he has Ophelia just happen to be walking in the very place they know Hamlet walks in the lobby every day, so they can spy on the conversation.  Polonius is also a great source of verbal irony when he frequently insults himself without knowing it. He tells the queen, “brevity is the soul of wit,” meaning that he entirely lacks intelligence, since he is incapable of saying anything briefly.  When the queen asks him to get to the point with fewer artful flourishes of language, Polonius says, “I swear I use no art at all,” meaning that this is not pretentious language for him.  He’s admitting that blathering on and on is his natural way.  He then proceeds to blather on some more about “a foolish figure.”  Ironically, we realize that HE is the foolish figure, but he never gets it.

Claudius frequently lapses into iambic pentameter during his soliloquies.  Considering that a king is supposed to be a very formal person, it makes sense that he would speak in a regimented pattern.  For example, his act 1 scene 2 speech to his court begins, “Though yet of Hamlet our dear brother’s death,” and continues for 38 lines of near-perfect iambic pentameter.  Claudius also likes to use analogies to explain things, especially when he’s trying to manipulate someone.  In act 4 scene 7 he fibs to Laertes that he didn’t punish the prince because Gertrude loves Hamlet, and “She is so conjunctive to my life and soul / That, as the star moves not but in his sphere, / I could not but by her.”  Another technique Claudius uses, and again usually when he’s manipulating others, is the epithet, or startling adjective, for effect.  In act 4 scene 7 he tells Laertes that a Frenchman previously visited Elsinore who was so good on horseback that he seemed “encorpsed and demi-natured / with the brave beast.”  Such elaborate details distract Laertes from Claudius’ true purpose, to further pit him against Hamlet.

Rosencrantz and Guildenstern speak in paronomasias, or puns, in act 2 scene 2 as a way to buddy up to Hamlet.  When the prince says he has no ambitions, just bad dreams, they try to lighten the mood by playing on his words.  Guildenstern adds, “dreams, indeed, are ambition, / for the very substance of the ambitious is / merely the shadow of a dream.”

Even Gertrude employs some rhetoric when she uses metonymy in act 1 scene 2, where she implores Hamlet to “let thine eye look like a friend on Denmark.”  By Denmark she really means that Hamlet should be friendly to and accepting of the king of Denmark, his uncle and new step-father, Claudius. 

And the list goes on. In fact, it seems that the only sane character in Hamlet who doesn’t use such literary techniques is the only one not trying to manipulate anyone – Horatio.