Y'all ain't never seen no redneck f'real if ya'll think thas how they be talkin'. Iffen ya wanna be real accurate like, ya gotta get it that there's a many diff'rnt ways o speakin down in tha good ol south.
Texans accents vary dramatically from, say, Mississippi or Alabama. Texas accents are what you usually see in movies, though not entirely accurate. That above is more of a generic southern affect, while a Texas one would keep the dramatic use of y'alls, but would actually use proper grammar because they have a dignified, educated way of speaking, just in a very odd way.