Their relationship is very important as Prospero and Caliban represent different worlds, the civilised and the uncivilised world. Prospero being the educated civilised character who invades the native Caliban's island. Caliban is a disrespectful and is disobedient.
The immediate impression of the relationship between the, uncivilised Caliban and the authoritative Prospero is that it is one of aggression and hatred. Prospero directly insults Caliban with names such as, "abhorred slave" and "a thing most brutish." Prospero's language is very harsh and degrading towards Caliban as he describes Caliban an evil savage like animal. Prospero even insults Caliban's mother and father in his first speech to Caliban.
'Thou poisonous slave, got by the devil himself upon thy wicked dam, come forth."
Prospero is not only saying that Caliban's father is the Devil himself, but he is also saying that his mother (the dam) is wicked and bad and the cruellest she could be. Even though Caliban frequently curses Prospero, his language is still not quite as offensive and malicious as he doesn’t directly insult Prospero Instead he wishes curses upon his master.
‘’All the charms of Sycorax toads, beetles, bats, light on you!’’
This curse in particular is one full of natural images, which suggests Caliban can relate to nature and his surroundings and this helps to emphasise that Caliban represents the native of the island. He relies on his mother for support and defence for his actions by saying “All the charms of Sycorax." He clings to the only security he has ever known. This shows he still acts like a child and doesn't have the power to stand up for himself. It also has connections with witchcraft, which is another insult in itself as it would be against Prospero's religion.
The language used in the curse doesn't quite equal Prospero's insults, which gives the impression that he is not as educated as