Germany’s many, diverse dialects are a fascinating study in the previous kingdoms that Germany used to be comprised of–formally. Informally, the regional dialects in Germany provide a beautiful kind of regional patriotism (as they are not likely to call themselves “patriots” or “nationalists” unless their political views are, shall we say, less than tolerant...).
The Deutsche Welle has created a wonderful resource on German dialects, which I highly recommend for intermediate and advanced learners. Click here to see Deutsche Welle's Dialekt Atlas!
Viel Spass dabei!