I have a granddaugther who was born totally deaf. She learned to sign and was quite good. They put cochlear implants in both her ears at about age 2 years. We referred to the day they went to start the implants we jokingly called it, Lacey,
Plugged in. When she heard the first sound, she cried. It scared her.

The potential in evolution is that sign language preceded spoken language.

I learned sign language years ago, but let it slip. I began practicing it a few years ago as something to do while commuting for hours each way to a Thailand/Malaysia border town where I was teaching. I had to give it up, though, as I rapidly began to think in ASL and suffered constant frustration from having to squelch my urge to sign instead of talking.
Plus, ASL can say a lot with the minimum of signs..so more efficient than most languages.

Great stuff. Thanks.

Great question