i've got three places in mind:

eastern central rockies

northeast bosnia

southern siberia

just gotta keep stackin and one of them is gonna stand out for some reason

we have english on one, i already know a decent amount of serbo croatian on the other, and last one knowing serbo-croatian helps a lot with russiand and plus i have some bulgarian

these are my preferred locations becaues they are high altitude and far from the coasts (the central mediterranean is a shallow basin relatively speaking)