In a recent conversation with a British friend, he and I reflected on evolution of various English words. Both history and geography are factors in changing word definitions, we decided. For example, in England, the word "dame" means a distinguished lady, while in America, it's come to more or less mean any woman. Our conversation drifted to changes in respectability or grammatical correctness of given words. That topic leads to the inevitable--"ain't."
Dahlem, Glenn G.
"Ain't Ain't the Same No More,"
4, Article 18.
Available at: http://digitalcommons.butler.edu/wordways/vol45/iss4/18