We bought a book called: "Teach Your Dog To Read" by Bonnie Bergin, Ed.D. and have started working on "Sit" and "Lie Down."
According to the book, it goes beyond just symbol recognition. Some dogs can actually get to a point where they interpret symbols they have not seen before. I think that Jeeves can at least get to the average 20 words or so.
Also, it may give us a tool to deter Jeeves from doing things like eat grapes off the counter, eat leftover slices of pie, or eat rising bread dough. Because we can leave signs up to discourage him. I'm not holding my breath on this one, but imagine if it did work.