Throughout the whole Destiny franchise, we've seen pretty much every single enemy faction speak english (or the english/chinese/russian hybrid language they use in the tower), from Variks, to Oryx, then Ghaul. Evidently, our alien foes can both learn and speak our language, but I can't remember a single instance where humans (including awoken/exo) have spoke to an extraterrestrial in their language. I can imagine Toland, Eris, and most warlocks can read Hive runes, but have we ever seen them speak the hive's language? Maybe i'm just misremembering, though, it's been awhile since i read the lore.