Doublethink: the changing of things that go against the thoughts of others, even when they think they're right, which changes the overall perspective of the person. An example being convincing someone 2+2=5
Doublespeak: words that undermine the true meaning. Things like the ministry of peace being the military.
ministry of peace
Newspeak: the official language of oceania that is made up of words to restrict the english language, an example being ingsoc, which means english socialism.