If you're not lucky enough to be from the South, well bless your heart. If you can't speak our language, here are a few Southern-isms you'll need to know. And no, Florida doesn't count as the south.
(To) be too big for one's britches: To think too highly of oneself
Ex. Lisa is getting to be too big for her britches. Her mama needs to jerk a knot in her hide.
Britches: Pants
Ex. Dangit John, you tore another hole in your britches.
Bless his/her heart: Usually followed by sad news
Ex. Did you hear about Jenny? Her brother was in that four-wheelin accident right after her dog ran away, bless her heart.
Bless your heart: Either an expression of sympathy or of thinly veiled disgust, very different from bless his/her heart
Ex. She cut me off in the Target parking lot with her buggy! I just looked at her and said, "Bless your heart, I guess you didn't see where you were going with that hair floppin in your face, Beth does great hair over on Main Street. Tell her I sent you."
Can't carry a tune in a bucket: Unable to sing
Ex. It's a good thing the church choir doesn't have auditions, cause Anne can't carry a tune in a bucket.
Cattywampus: Askew, crooked
Ex. Go fix that picture frame, it's hangin all cattywampus.
Clod-hopper: Large, heavy shoes
Ex. Buddy, I don't need you tracking mud all through the house in them clod-hoppers, so take them off at the door.
Directly: Eventually
Ex. Quit your fussin, I'll be there directly.
Fixin' to: getting ready to/prepared to
Ex. I'm fixin' to go to Wal-Mart. Y'all need anything?
Gussied up: Cleaned up and dressed nicely
Ex. Rita got her kids all gussied up for Easter Sunday, but Lord knows they're caked in mud every other day.
Hold your horses: Slow down, chill out, be patient
Ex. Hold your horses, Anna, we'll get there eventually.
Kin/Kinfolk: Family, in small towns, probably the entire town
Ex. Yeah the Hucks' are my kinfolk, but I ain't claiming Josh.
Knee-high to a grasshopper: Very young, small
Ex. Oh my goodness, look at little Sarah all grown up! Last time I saw you, you were just knee-high to a grasshopper!
Ornery: Bad-tempered, stubborn
Ex. Granddaddy sure has gotten ornery in his old age.
Reckon: Suppose
Ex. If she don't get out the house, I reckon I'll have to drag her.
Rubber-neck: To drive slowly past
Ex. Traffic is backed up all the way to First Baptist with people rubber-neckin at that wreck Ella was in.
See someone's Christmas: The person in question should put more clothing on
Ex. Allison needs to wear a longer dress, you can see her Christmas. She needs to keep it wrapped.
Tater: Potato
Ex. We're havin taters and onions with the fish fry tonight, so y'all come hungry.
Yonder: A place
Ex. Go cut off the light in yonder.