I really expected a lot more from this. While I usually prefer well written background information to generic optional rules, the writers have gone too far with a good thing here. Though it's well written, it's seriously lacking in real substance. The presented incantations cover only a few very specific situations, and in most cases, you're probably still left with designing incantations by yourself, without getting any useful help. It's really just the basic incantation system from the 3.5e SRD with a couple of additional sample incantations.