Yesterday I was at school, waiting in the rotunda for class to start. I was listening to my voice mail on my phone, and one of my profs passed by. I'd been emailing with her earlier in the day, and as she passed she gave me a questioning look and mimed writing with a pen. She was asking, "Did you get my email response?" I nodded and gave her a thumbs-up.
This got me thinking about the evolution of sign language. If I'd been trying to convey that message, I would have fluttered my fingers on an air-keyboard.
Another one: If you were driving a car and you wanted directions from someone stopped at a red light, you'd probably make the old roll-down-your-window gesture. This despite the fact that more and more cars have automatic windows. That seems way more effective than trying to mime someone pressing a window button, right? I wonder if someday people will be wildly pin-wheeling their fist at another car and think, "Jesus, where did this come from?"