Here are a few words that James knows how to sign that I forgot to mention... Airplane, bus, and wash hands. That makes the total word count 27 for signing. He also says "Ga" for "Go" and "Caw caw" for bird, so maybe that would bring it up to 29?
Anyway, he is getting a lot more vocal and I think one of these days he'll talk. When he's ready. :-)