All y'all is used (rarely) for emphasis, not to pluralize. "I got presents for y'all!" is plural. "I got presents for all y'all!!" is also plural. It's just emp

All y'all is used (rarely) for emphasis, not to pluralize. "I got presents for y'all!" is plural. "I got presents for all y'all!!" is also plural. It's just emphasizing the number of people to underscore, say, generosity. That being said, not everyone in DFW talks that way. Many prefer a more subdued midwestern style. The metroplex is full of transplants from all over, so there isn't a lot of pressure to talk like a local or something.