I finally voted for:
I'd be happier if at least the formation names were in English
I had to think about this for a while. I speak only english, and sometimes struggle with that

. (After all, that's why we fought the war, so we all wouldn't end up having to speak German

)
However, I enjoy learning some of the original language names for units and equipment; and some nuances are lost in translation.
I also very much appreciate that this is an international game and community, and don't think english should be the exclusive language used.
But in the end, the one thing that we almost all have in common is at least a basic grasp of english. It's the closest thing we have to an international language.
Using english for only the formations is probably the best compromise. I think it will speed up the OOB learning curve and encourage people to experiment with a greater variety of nations. But we won't lose the orignal flavour of the units.
cheers,
Cross