Applying Dolby Prologic IIx made all speakers except the center go dead on the English 2.0 track. Looks like 2-channel mono.

Would doing something like using English mono minus the L & R channels of the Russian 5.0 track make a good center channel (assuming they sync properly) or would that still not be quite right?

Edit: OK. Never mind. Testing the Russian track further: L minus R and R minus L completely neutralizes the channels. Definitely not any sort of true surround. I assume the surrounds have some sort of delay applied.

Not worth the effort.