England's slavery in Africa was used to benefit the economy of England. The slaves were seen as creatures without identities, just as the monster Caliban was viewed.
The use of language for Caliban was to curse and mock his master, just as Prospero said in Act 1; [Caliban] never yields a kind word (Act 1.2 lns 307-308). His language is used for receiving orders rather than communication. Prospero continuously banters Caliban with words like, "poisonous slave," and "hagseed," (Act 1.2 lns 319; 365). Caliban learns these words and expresses his own harsh words to his master. This scene is important in depicting the relationship between master and slaves. Shakespeare shows the indecent actions of verbal and physical abuse of the British on the inferior, weaker Africans through Prospero's actions. Prospero also physically harms Caliban by using his magic to give the monster pains and cramps. .
In this same scene, an important quote is said by Caliban that shows the irony of his learning the European language. "You taught me language, and my profit on't is I know how to curse" (Act 1.2 lns 363-364). What Caliban is saying to Prospero is that he was taught language only to benefit Prospero, in that Caliban is able to understand orders and know when he is being verbally abused and controlled. Caliban also says how his only benefit is his ability to curse Prospero for enslaving him. The knowledge of language also removes the excuse of Caliban's behavior on his primitive nature, and conforms his character to be like a "civilized" European. Here the parallel to British imperialism is great in the sense that the slaves were taught commands in order to perform duties by slave owners. Through violent words both the slaves of the British and Prospero's slave Caliban knew when they were being disciplined, and when they had to obey.
Prospero's use of magic imposed physical pain on Caliban. When pain was inflicted Caliban resisted to attack in fear of being in more pain.