I'm starting this because I did a search and haven't seen a single thread just about this really great singer/songwriter, although there are several that mention her. She doesn't really consider herself a folk singer. But her best songs are accoustic and thought provoking, so many categorize her that way.
She has a very powerful voice and is extremely soulful. She captures the feeling of a song as much as anyone I've heard. If you haven't heard her before, she's worth listening too.