What is unusual about they way Dickens has the narrator talk?

The first-person narrator of Dickens' Great Expectations is an adult Pip who tells the story in his own voice and from his own memory. What is distinctive about that voice is that it can so intimately recall the many small details of a little boy's fear and misery, as well as the voices and dialects of others—from the rough country speech of Magwitch and Orlick to the deaf Aged Parent's loud repetitions or the mechanically predictable things Jaggers says.