One way to seek out the accents is by reading letters written by somewhat uneducated folks. They spell phonetically and sometimes you can follow the accent by reading the letters aloud. This came to me in the Confederate Museum in Richmond, VA several years ago. Soldier letters home actually spoke with southern accents. Fascinating!!
One of my favorite written accounts from the time is,
DIARY OF A TAR HEEL CONFEDERATE SOLDIER.
http://docsouth.unc.edu/fpn/leon/leon.html
Even though the author was a Jewish kid living in North Carolina, with parents in New York, you can still get a sense of a Southern Accents in his written words.
Here are a few entries as a sample. The whole diary is great reading. Diaries like this were very rare from regular soldiers in the South.
December 3 - Katz and myself went to Petersburg to-day. We met with friends, and the consequence you can imagine. The headache we had next day was caused by too much whiskey.
December 21 - I went to the creek to wash my clothing and myself, and when I got back the water had frozen on my head so that I was obliged to hold my head by the fire so as to thaw it out. Wortheim’s eyes are so bad that he can hardly see. Sam Wilson broke his shoulder blade.
December 25. - There is nothing new up to to-day, Christmas. We moved our camp a little piece. Eigenbrun came to see us to-day from home, and brought me a splendid cake from Miss Clara Phile. This is certainly a hard Christmas for us - bitter cold, raining and snowing all the time, and we have no tents. The only shelter we have is a blanket spread over a few poles, and gather leaves and put them in that shelter for a bed.