So, Sam's signing something. And I don't understand. I ask for a clue:
"What's it like, Sam?"
"Like aeroplane, Mummy."
Amazing, he's learning to categorise objects and knows that there are elements in common. Similarly the other day with Nanny, moving things from one bowl to another - Nanny wasn't responding to Sam saying "one", so he helped her out with the clue "one, two, three, Nanny". Clever boy :)