I think the futuristic gameplay planned for BF6 will be international 'factions' that will be battling against each other. So not old-school thinking of US against China, or Europe against Russia etc. Thereby your language selections and soundtrack will not be like "somebody not speaking my language is my enemy". He could actually be your next great friend in the fight against your common enemy faction! ;o)
Regarding audio, then the most important thing to get would be "proximity chat", so friendlies you are battling together with, you can all talk and listen to each other. So you can communicate with your friendlies nearby around you, not just your own squad.