A really nice touch in Crysis (the demo) is the feature that lets you have foes speak in Korean. I love this. Replacing the stupid English taunts with incomprehensible (unless you speak Korean) dialog smartens the atmosphere up a bit, and gives the game a nice level of realism.
Unfortunately, the only way to get this is to play on the highest difficulty level, which completely ruins the realism in other ways. On the highest level, the bad guys have telescopic vision, flawless aim, and intense paranoia. The foliage in the game is great, but they seem to be able to look right through it and determine that the slightly dark shape sitting motionless in a bush 100 meters away is:
a) An enemy
So the choice comes down to fighting cross-eyed idiots with ridiculous combat taunts delivered in pain-inducing fake accents, or fighting cheating killer robots who speak Korean.
Still, "authentic" enemy language is always a nice touch. It sounds like Velvet Assassin takes this approach as well. One can only hope this is the start of a trend.
Shamus Young is a programmer and writer by trade, videogame nitpicker by inclination. If you have the patience for more of his ramblings, they can be found at ShamusYoung.com.