I actually prefer that they speak english. I don't mind if the units chit-chat in their native languages(FotS) but i prefer "INFAAAAANTRYYYY" over "Whatever that is in latin". While i found the accents in Med2 quite funny it became abit ridicilous. And i am not a native english speaker.(In Empire, the country i was in was playable ,and it felt really awkward hearing them respond in your own language. Then again, overall voiceacting in Empire was pretty bad)