If they don't implement this with the British, they never will. Mark my words. Why? Cause finding the voice actors, designing their characters, lines, and etc, getting them in the studios and paying them just doesn't pay off at this stage of the game... This will never happen.
if i recall correctly the sound files for the German and Russian languages are "there" relic just has to make slight reprogramming/coding adjustments in the sga files and they should be golden. it nots as hard as it looks by the way of it. im thinking relic might have been lazy and forgetful or they are too busy making the brits