So, the government of Oceania in 1984 creates a new, altered cersion of English to make its people easier to control.
What about the opposite?
A dictator wants to make his people harder to control, so that any invading nation would have to go through an ungodly amount of trouble to subjugate them.
Could he do it?
I'd imagine he'd start by gradually altering the language to be more complex, more foreign to neighbouring languages, and popularizing words or phrases that are harder to interpret by an outside listener.
He has already completely isolated this nation from the surrounding region, and the language present there is pretty unusual for the region, think Hungarian or Basque.
I am however unsure if this'd be enough; other ideas would be helpful if you think it could be done.