I found a map of North American dialects this morning and found it interesting. According to the map, people in East Tennessee speak a dialect called Inland South, while people in Middle Tennessee speak a dialect called Lowland South. Grandmother and Granddaddy Ogle, who lived in Middle Tennessee, both spoke with an accent that I thought of as being "more" Southern than the accents I heard around me in Knoxville growing up. Their accent more was like the drawl I heard portrayed on television and in movies as how people spoke in the antebellum South.
My own accent varies. I make an effort not to reveal a country accent when speaking in court or when transacting business, and I am more apt to sound country in casual conversation than in formal conversation. However, because of my lack of an accent , it is not unusual for me to be asked, "You aren't from around here, are you?"
I can lay on an authentic country accent if I think about it, and I'm likely to slip into one if in the company of people with more of a country accent than I typically use, or when someone questions my Southerness. I lived in North Carolina for a few years in my early twenties, and the country accent on that side of the mountains is slightly more nasal. If I go over there for a weekend to visit friends, I pick that back up, at least for a few days. (The map classifies the part of western North Carolina where I lived as Inland South, but I hear a difference over there.)
One of my most memorable days in law school was during my first year and involved a Southern accent. My civil procedure professor had the most wonderful South Carolina drawl, and he was a practitioner of the dreaded Socratic method. He called upon a student, and the student answered him in his best interpretation of the professor's drawl. The professor was not amused, and the student was expelled from the class.