This got me too. What really gets me is that all the Russians speak to each other in English (except the soldiers), and half of the propaganda is in English too. I'd understand if You and Nolan North were rolling through the island with a Babel Fish type device in your ear, but to be honest, the game would be better in Russian with English subs.
Let's face it at some point somebody at Raven said "You know what, balls to continuity, kids don't wanna read, they wanna shoot".
Let me explain it for you, the reason it's 30Gb is that Midi-chlorians the tiny elements that make the physics and particle effect possible, can't be controlled in small numbers, so you need at least 30Gb to lift a Tie Fighter. Hope that cleared it up for you.