Referring to Jane, Holden says
She was sort of muckle-mouthed. I mean when she was talking and she got excited about something, her mouth sort of went in about fifty directions, her lips and all. That killed me. And she never really closed it all the way, her mouth. It was always just a little bit open, especially when she got in her golf stance, or when she was reading a book. She was always reading, and she read very good books. She read a lot of poetry and all.
In the passage above, what does Holden's description of Jane reveal about her character?