A common critic we hear about an EU wide army is What language are they gonna speak but let’s forget Europe 2024,
Rome had a huge empire over the whole Europe, I may be wrong, but I don’t think that commoner spoke proper Latin in remote province. What happens when they join the legion ? Would the units be split by origin region (Dacian with Dacian, Lugdunumese with Lugdunemese) with only officer speaking latin ? Or would you merge legionaries from different province (So you have Tingitanian, a Lustitanian and a Thracian in the same unit) and give them a crash course in military latin (the way the french foreign legion does? ) Even going as far as Rome, Karl the great empire also spread over half of Europe, and modern European nation used to be way more multi-lingual than they are today, and most likely a random southerner/northerner in Britain, France or Germany couldn’t talk to each other.
So how did ancient armies managed the language question ?
While I have no doubt that officer (and even most NCO) do know more than basic english, I have some doubts regarding the typical high-school drop out who enlists in the infantry.
So if you need to talk about geopolitic, aircraft maintenance or even coordinates two different group of soldier, NATO english would be fine. But how would a multi-lingual crew works on a warship ? What about a multi-lingual patrol ?