Southern slang:
-y'all
-you'ns
-I 'reckon' (means 'I guess so')
-britches (pants)
-soda (pop, coke, soft drink)
-drawers (underwear)
I know there are a poopload more, but I can't think of any right now.
I can tell you aren't from the south (are you even American?). I have never heard "you'ns" and I have lived here all my life. I have only heard it on T.V. from people who have probably never even been to the south and are responsible for giving non-southerners like yourself false conceptions about how we really speak.
Also, I don't think of "Soda" as being a southern term at all. Again, are you even American? NO ONE in the south uses the term "soda." It's funny you even put "soda" on your list because many southerners often talk about how "soda" is a "yankee" thing. Down here we call all soda-pop Coke. That's right, no matter the brand name, we call all soda "Coke." To say "give me a coke" might mean to grab a Mountain Dew or a Pepsi.
Here are a few southern expressions off the top of my head:
"Coke" -- all soda
"fixin" -- verb. means I am about to do something. "I am fixing to get in my car and leave."
"y'all" -- of course I have to mention y'all. However, many northerners get it wrong. They think "y'all" refers to the singular, when in fact the term is ONLY used when addressing more than one person.
"Lightning Bug" -- a southern term for firefly.
"Egg on" -- means to arouse or irritate -- "Why do you have to egg him on, he is obviously mad already."
"rile up" -- exactly the same as egg on. "Shut up, you are about to get me riled up."
"Fit to be tied" -- means that someone is angry. "He is so mad he is fit to be tied."
"No 'count" -- My father said this a lot. It means "worthless." For example, "That man sold me a used car that ain't no count."
"ornery" -- adjective.. It means to have an irritable disposition.
"reckon" -- this one is interesting because it is a Middle English word that is no longer used in England. It is usually only used in the southern U.S., at least as a verb. "I reckon he is right, I do need to sell my car."
"holler" -- used as a noun. The word is probably a bastardization of "hollow" which means valley. "I saw Bill, he was walking down in the holler."
"holler" used as a verb --- Holler can also be used as a verb. It is correct to say "he was hollering at me." However, southerners will often use "holler" in the sense of "Hey if you want to go to the ball game just give me a holler."
"Yankee" -- refers to anyone north of the Mason-Dixon. So, when the Brits call Americans "Yanks" they don't know that southerners are NOT considered Yankees by definition.
"ain't" -- everyone uses ain't now, even the Brits. I wonder if this is truly a southern idiom or not.
"might could" --- this is more of an incorrect speech pattern, sort of like a double negative, than it is a southern idiom, but many southerners, including me, say it in everyday speech. For instance, it is correct to say "I might be able to do that." But many southerners say "I might could do it."
"trotline" -- a trotline is a fishing line that is put out to catch fish while one is away. Sort of like a net, except it is actually a line with hooks.
"Sweatin' like a whore in church" --- This one should be self-explanatory.
"naked as a jaybird" -- this one I hear a lot. Self-explanatory.
"Deader 'n a doornail" -- means overkill. "He is deader than a doornail."
"no sense" -- means stupid or idiot. "John is an idiot. He ain't got no sense."
"Hit a lick with a snake" -- Means lazy. "That boy ain't hit a lick with a snake in two weeks, he just sits around all day."
"no dog in that fight" -- Obvious meaning. Means you have nothing to do with something. "Don't complain to me, I ain't got a dog in that fight." I assume the term originated with the fact that many people used to hold organized dog fights decades ago. Dog-fighting was actually brought the the USA from Britain.
"I suwanne" -- I hear this one a lot from my parents, but it is not common amongst younger people. It means "I swear." However, it is usually used while disgusted. For example, if you drop a glass of milk on the floor, you might declare "I suwanne."
"livin' high on the hog." -- Just means you have lots of luxury. "John just won the lottery, now he will be livin' high on the hog."
"uglier than a mud fence." ---Just a way of expressing how ugly something or someone is. I have no idea the meaning of it, but I guess someone long ago thought muddy fences were ugly?
"damn near" -- this is one I use a lot and hear a lot. For example, here is how I might use it: "I saw John the other day, he has gotten old. He must be damn near 70 now."
"strong as a mule" -- just an expression to describe the strength of someone. In my area I hear people say "strong as an ox" more often however.
"hollow leg" -- pronounced "holler leg"-- This is used to describe someone who eats a lot. For example "You have already eaten two plates of food, you must have a hollow leg"
"Whistlin' Dixie" -- This is used to describe senseless or inconsequential speech or chatter. For example, "You don't need to tell me what I already know, you are just whistlin' Dixie." I assume this one derived during the Civil War because obviously Dixie was defeated by the Yankees. So to "whistle Dixie" meant to whistle the theme song of the confederacy. Obviously since the confederacy was defeated, the term was used to describe something that had no consequence. Why whistle Dixie if Dixie is no more?
"beat with an ugly stick" -- means to describe someone who is ugly. "That boy is so ugly he must have gotten beat with an ugly stick."
"ugly tree" -- same as ugly stick, except it is often said "He is so ugly he fell from the ugly tree and hit every branch on the way down."
"mess" -- used as a noun. For instance "I saw the herd of cattle coming, there was a lot of 'em -- a whole mess of 'em." This term can be used to describe "a lot" of any object. It is often used to describe fish. "I caught a whole mess of fish." Again, it can be used to describe "a lot" of anything.
"directly" --- I like this one and use it a lot. It is used to describe a short time period. For example "I am going to go pick up a six-pack of beer, I will be back directly."
"homemade sin" -- Used to describe how ugly someone is. "That girl is uglier than homemade sin." I have no idea what the hell homemade sin is, but it is funny.
"400 hell" -- LOL, this is one I used to hear people say. I have no clue as to its origin or what the hell it means, but I will use it in context of a sentence. "Man I am so drunk, too drunk. I am drunker than 400 hell." I am not sure if this is an actual southern expression or the invention of a few people who happen to live in my area. I have googled it and can find no mention of it anywhere.
" 'Ole " -- Ole is interesting. I use it almost everyday. It probably is a bastardization of "old." It is likely of Scots-Irish origin and originated by the scots-irish immigrants in the south. It is just an expression one would use sort of like an adjective. For instance "Ole John is crazy." I use it typically as an adjective in front of someone's name. But it can be used to describe any person or any object. For instance "My 'ole DVD player just screwed up." It doesn't have the same meaning as "old." It is just an expression that can be used to describe any object or person old or new. The University of Mississippi is also known as 'Ole Miss.
There are many, many more southern idioms, but these are ones common to my area and ones I hear often today. Many of the ones you will find online in slang dictionaries are either outdated or used in other areas of the south. I am not familiar with some of them myself.