Name: Hand gestures.
Age: Older than language.
Appearance: Demonstrative hand signals encoding commonly understood meanings.
I don’t follow you. Can you give me an example of what you’re talking about? Certainly: placing a fist alongside your head, thumb and little finger extended, in the manner of a man trying to scratch his chin and his ear at the same time.
OK. And what does that mean? Can’t you guess?
Does it mean: “My ear and my chin both itch”? No! It means: “Call me.”
What? How do you figure that? It’s miming holding a phone – the thumb is the earpiece, the little finger is the mouthpiece, and the fist is pretending to grab the long bit in between.
You’ve seen a phone, right? I guess it wouldn’t make much sense if you’ve only ever used a flat, rectangular mobile.
You’re correct, it wouldn’t. Give me a better example.