Answer:
Newspeak, doublethink, and The mutability of the past
Explanation:
1. Newspeak. Newspeak is the official language of all party members, as the purpose is to eliminate all thoughtcrime.
2. Doublethink. Doublethink is very common amongst the Party, and quoting from CliffNotes, “doublethink is the act of holding, simultaneously, two opposite, individually exclusive ideas or opinions and believing in both simultaneously and absolutely. Doublethink requires using logic against logic or suspending disbelief in the contradiction.” The three slogans inside the novel, “War is Peace,” “Freedom is Slavery,” and “Ignorance is Strength,” are all examples of doublethink.
3. The mutability of the past. As Orwell writes in the beginning chapters III and IV, Winston encounters in his memory that Oceania actually allianced with Eurasia and fought against Eastasia, yet all broadcasts of the party suggests that Oceania had always done the vice versa. Also, he and his comates have had no memory of Big Brother until very lately, yet documentations have stated that Big Brother has been influencing Oceania since the 1930s.