My dad was one of those guys who would brag about having never read a book in their life. He subscribed to National Geographic, but I'm pretty sure just for the pictures.
I think people like that lack an internal monologue. I've read that like one in twenty don't have an internal monologue, like, as I'm writing this, I'm also saying it in my head. Or when I think, I think in my head. They lack that. They think in emotions and objects, but not language.
Always a strange concept to me.