One of my favourite C. J. Cherryh books is Cyteen (bear with me for the relevance). One of the impressive things about it is the portrayal of much of the plot from the viewpoint of the growing clone as she's guided into becoming a version of the original with most of the same (extraordinary) capabilities. That uses precious child-like viewpoint very well, including the use of language for her internal thought processes. I haven't actually read The Graveyard Book. It's on $DAUGHTER's shelf, alongside Coraline and Fortunately the Milk (we've seen the film of the first and I've read the second to her). Is the simplicity of the sentences here something of the same thing, perhaps?