When I lived in Germany, I noticed German extended quite far into some of the neighboring countries, insofar as I could speak German to quite a few people in Prague, and they would understand to a semi-decent degree, and when I travelled through Slovakia many people also knew German. I figured Germany was a fairly central, and influential country, combined with those countries' close proximity to Austria as well it wasn't entirely surprising.
To the same regard, I've noticed French is also quite popular in a lot of W. Euro countries, I could speak the little I know as far as the southern Netherlands and Northern Italy. I do not have knowledge of any other languages besides, so it has made me curious…
In your country, where do the languages separate? If you cross a border, is it an instant switch, or will you meet people for some time that can at least understand your own language, if not fully speak it? Have you met many people outside your country who you can speak your native language with regularly?