Living my whole life in Arkansas in the United States, I’m certain that if I were is never used by locals. Instead, phrases like if I was and you was and they was have all replaced their equivalents in other regions.
I’ve heard these so often that I think it’s necessary to ask if they are grammatically correct as a part of a southern dialect. Does their appearance in a certain region as acceptable excuse their application in formal writing?
Personally, I indeed believe that anything not found in generic, “accent-free” areas should not be considered correct. But officially within a southern U.S. dialect, are these constructions grammatical?