Its going to get funnier the longer he avoids answering lol. In my mind, he could be referring to anything from double speak (doublethink), double entendres, puns, double meanings, etc. He needs to show some of his thinking so we can answer intelligently
"War is Peace" is doublespeak; an inherent contradiction. Anybody can say it and still see the contradiction and believe that it isn't true. Doublethink is the internalization of that doublespeak. A Party member says it and sees no contradiction. Deep in their hearts, they understand that to be in a never ending war is to experience neverending peace.
All that to say that doublespeak was certainly a thing in the novel, as it labours on the distinction between doublespeak and doublethink.