I don't know about its accuracy, but this quiz is certainly funny, if nothing else. I think I rated so high (if you can call it that) in Southern slang because I have worked for decades with people whose roots are in the South, no matter where they lay theys haid at:

Your Slanguage Profile

Southern Slang: 75% Aussie Slang: 50% Canadian Slang: 50% Prison Slang: 50% Victorian Slang: 50% New England Slang: 25%