In Caliban speech in act 2 scene 2 , Shakespeare uses a few similes for example he says “Sometimes like apes , that mow and chatter at me.” In this simillie Caliban is saying that  has cursed that he can he voices speaking to him in other words prospero has basically made him a mad man .

Shakespare also uses a violent way in Caliban speech.He uses this way of text because if ur up to date on the tempest you will know that Prospero has cursed Caliban because Caliban attempted to rape his daughter , Miranda and because of that Caliban is very angry and mad in his speech .