What is the author's style in The Neon Bible by John Kennedy Toole?

The language of the novel is formal and proper, much unlike what you would imagine David actually sounded like. He is speaking as though he is wise and educated beyond his years. This language choice is affective in a positive manner because it allows the reader to concentrate on the events of the story and not the specific type of dialog of the narrator. It may have been detrimental to write the story the way that David really spoke.