"Both series are written in first person; Harper's voice sounds fairly realistic for a teen, whereas Bella's is some bizarre mix of monotone melodrama punctuated with unbelievable vocabulary."

I don't remember if you heard about this, but at some point Jane_Drew_ and I got into a conversation where we had a revelation regarding Bella Swan's narrative voice and it turned into a Writer's Commandmant: A character shalt not have a larger vocabulary than his or her writer. Plainly put, if you can't use the word correctly in a sentence then the odds are that they won't pull it off either.