We're not all illiterate.
I'll put money on him being from Maltby though, it's about the level of literacy you would find in that area. Years of knuckle-dragging and in-breeding.
I'm also from Rotherham originally (went to a Rotherham comprehensive / sixth form) so I'm allowed to jest

And yes - Maltby does seem to be a bit of an un-evolved armpit, even by Rotherham standards.