On that note, it tells me enemies are supposed to not speak English, but they still are.
I think only Delta difficulty have them speak korean. At least in my game, they do speak korean.
What I hate about choppers is that they have perfect vision and shot you even if you are under some plants, while cloaked and still. I like playing ninja and that ruins it.
Oh gawd, I remember the choppers. My first run-through, on the level where half the map is a long river you have to traverse, I didn't know you could kill choppers with anything short of a rocket launcher, and I didn't have one. Cue me spending an hour (!) darting between bushes, letting my cloak recharge, and crossing my fingers that I wouldn't be spotted and insta-killed.
And yes, Korean speech is only on Delta difficulty. One of the 'features' of Crysis was that difficulty levels did something
other than just multiply enemy damage and health; the game removes a bunch of the 'crutches' when you reach higher difficulties. Enemies stop speaking accented English; weapon turrets require you to actually be
in the turret to fire them; I believe you even stop automatically picking up ammo from weapons you pass over, though I might have that last one confused with Warhead.