Hi Bernie,

the bavarian slang is a very special form of the german language. I speak the Allgäu-slang and it is a bit more special. So if you hear a guy speaking that way: "Na gang i scho seit schtunda dur dia gegend und`s leit allat no koi bier it" ( now i am going since hours through the landscape, and i have not getting a beer til now! Wich is really bad for an bavarian) than you can be sure to hear an Allgäuer-Bavarian.
So if you like to learn Bavarian let know! But that is really hard!

Best regards

Ulrich ( Total bavarian native)