In Hendrickson, Robert. The Facts on File Dictionary of American Regionalisms. New York: Facts on File, 2000. p6 the introduction to "Whistlin' Dixie" we find (emphasis added):
Another Southern peculiarity is the use of ain’t among cultured speakers. Raven I. McDavid Jr. pointed out in American Speech that during interviews he made “nearly every cultural informant... in South Carolina and Georgia used ain’t at some time during the interview. In fact, one of the touchstones often used by Southerners to distinguish the genuine cultured speaker from the pretenders is that the latter are too socially insecure to know the proper occasions for using ain’t, the double negative, and other such folk forms, and hence avoid them altogether.”
Can anyone provide examples of the "proper" ("cultured") Southern use of ain't or the double negative, etc.? (Past web searches have produced only journalistic pieces along the lines of "10 things only a southerner would say..."; the cited work is the only good source of American regionalisms I have been able to find.) Contrasting improper usage also informative.
Illustrations from Georgia would be particularly appreciated.