Japanese and Chinese do this as well. Lots of different formality levels, and every region in either country has dialects that are incomprehensible to an unlear

Japanese and Chinese do this as well. Lots of different formality levels, and every region in either country has dialects that are incomprehensible to an unlearned outsider. In Japan, everybody learns Standard Japanese Pronunciation, and I've never had a problem getting around even in the boonies. In China, I believe there are still a lot of people that don't speak Standard Mandarin, but this number will continue to shrink thanks to the explosive growth of high-speed (Radio/TV/Internet) media in China.