Hey, what's wrong with giving the soldiers voices? Just make them "reaction" things - maybe showing state of mind? If one has low bravery, for example, and sees an alien, maybe a muttered "Ah, shuckeroonies"? But, of course, you'd have to have an option for turning trooper sounds off... [side note: I'd be interesting if the sounds for power/flying armor (or their replacements) would be garbled, like with sattelite phones. But that doesn't really jive with the date of the game, you could always use the Clancy-esque stuff...]