Just a few quick tips for anyone who is trying to write a "Southern" character, about that most Southern of words, y'all. The first tip is that's how you spell it. Remember that an apostrophe, outside of being used in a possessive, indicates missing, unpronounced letters. Y'all is short for you all; the "ou" is what's missing. Some people, and I have to admit some of these people are Southerners themselves, write ya'll, probably from the influence of words like we'll.
The other tip is that y'all is a second person plural only; it's not some sort of blanket Southern replacement for you. It can only be used to refer to two or more people. I think some observers get confused because they see person A talking to person B, no one else in the conversation, and hear y'all. But in those cases, more than one person is being referred to, even if not present. Examples:
"Why don't y'all come over and watch the game with us?"
In this case, person A is inviting person B's entire family over.
"I hear y'all need to find a decent quarterback."
In this case, person A is referring to person B's chosen football team.
"Do y'all need anyone right now?"
Person A is asking if Person B's firm is hiring.
And so on. What you have to avoid is something like this:
"Y'all look good in that shirt."
"Y'all shouldn't have said that."
"I'm going to punch y'all in the mouth."
In these cases, Person B knows that Person A is some sort of impostor, and will alert the authorities as soon as possible.