Kittyboy has the sign of the cross ALMOST down pat, except he does it backwards (the Catholic way). Obviously that's because he's following the movements of our hands as if in a mirror, so that'll straighten out with time. We were eating in a restaurant with friends once shortly after he'd started doing it regularly, and I forgot to cross myself before eating. He looked at me, said "Mm!" and crossed himself. He then was so taken with his first taste of fried okra that he crossed himself before every bite. Books that have icons on the front, he points at and crosses himself. The little photo album in which I have his icon cards is getting beat up and will need replacing at some point. Signing for Jesus is going nowhere, though he may have put together that the Baby in Mary's arms is the same person as the grown-up man by the same name, because when I point out a picture as Jesus, he signs Baby. That's partially owing to me arranging his icons in the photo album as diptychs, where the Theotokos and Child (Mary and Jesus) on one side are directly opposite the one of Jesus as a man. The Baby's name is Jesus, the man's name is Jesus, so when he does sign, he does Baby for both. We're putting the pieces together, albeit sort of backwards. Signing for Mary, he has figured out, although it's very close to the way he signs Cat, so if you're in a store and he does it, it might be that he saw a cat on something, or it might be that you're passing the Nativity displays. Context is key. Joseph doesn't need a sign - after I'd spent some time sitting with him at the manger scene going over "Jesus - Mary - Jesus - Mary", he picked up Joseph and SAID "Dadd-n!" (Daddy).
Horse and Cow we're also seeing, though he doesn't differentiate between the two. And both are very close to Hat. He stood by a set of shelves by the door and pointed, then put his fist up to his head. I guessed, "Hat? You want your hat?" because he does have a favorite hat he likes to wear around the house sometimes. He put his hand down, and then did it again. "Horse?" He turned and pulled the donkey from the manger scene out from behind the shelves. We've been calling it a horse because, well, it LOOKS like a horse, and when I called it a donkey, he signed Dog (doggie). Angels are still Birds, which I suppose follows a logic similar to signing Baby for Jesus.
I can't imagine what people did with really late talkers before they started sign language with babies. Were it not for Toilet (diaper change), More, Eat/Drink, and Night-Night, life would be sooo much more complicated than it is. With signs, we'll be able to start toilet-training without him necessarily talking yet, as soon as we get the skill of pulling underwear up and down. If we were waiting for him to talk, I have no idea WHEN we'd be starting. And he's learning the basics, the name for things, and how language is used, NOW, so that however late he talks, he'll already know all that.
Oh, and just now I may have seen him sign Jesus (he'd brought me the photo album to look at), and it's sort of a vague mid-level sign he does for a lot of things. A LOT of signs look like each other. But it's a start!