When I was in the 10th, most all of 1st and 2nd Bats learned German and 3rd learned the Slavic languages like Russian, Czech etc.
I was lucky enough to go to DLI for German and learned to speak Serbo-Croat during my 12 year stay in the former Jugoslavia.
I've got most of Northern and Eastern Europe covered except for Hungary which has it's own "special" language that no one can learn!