This is a somewhat unusual assignment, as most academic papers have thesis statements rather than hooks. The notion of a "hook" is more typical of journalistic writing, in which you introduce something intriguing, odd, or startling in order to grab the reader's attention.
If you are focusing on syntax and diction, your main theme will be Newspeak, the language that is being created at the Ministry of Truth in order to make any original thought or form of rebellion impossible.
One possible hook would be suggesting that Orwell is taking Wittgenstein's notion that the limits of one's language are the limits of one's world, and applying it to suggest that by limiting language, one can limit people's ability to think, as is suggested in the following passage:
Don't you see that the whole aim of Newspeak is to narrow the range of thought? In the end we shall make thought-crime literally impossible, because there will be no words in which to express it . . . .
Another possible hook would be to compare Newspeak to the language of text messaging. Both have a simplified syntactic structure, limited vocabulary, simplified spelling, and other features in common. In constructing your hook, you might ask if text messaging (or Twitter) limits thought in the same way as Newspeak does.