It's called Newspeak, and it is based on the strong version of the Sapir-Whorf Hypothesis, which has been largely discredited. It is now generally recognized that change in language does not correlate to a change in the thought patterns of the people using the language, so using a language like Newspeak to control thought is quite unrealistic. Languages are extremely flexible tools and people will use them to get across whatever concept they are capable of thinking, even if they have to invent new words for it.