Science and Religion come together to confirm my long standing belief; Adam and Eve used Sign Language and when they got kicked out of the Garden of Eden they had to learn to vocal speech.
NPR story from 2010
Signing Before Speaking?
…Armstrong says he thinks gestures involving the hands may well have been the earliest form of complex human communication.
Evidence from fossils supports that idea, Armstrong says. It shows that a modern hand capable of sign language evolved not long after our ape-like ancestors stopped walking on their knuckles a few million years ago.
In contrast, the modern vocal tract seems to have arrived much later, Armstrong says.
And the modern version of a gene called FOXP2, which is important for speech and language, didn’t appear until perhaps 100,000 years ago, he says
So early human ancestors probably used gestures to communicate, Armstrong says, because “articulate speech of the sort that we employ would have been probably difficult.”
Also, sign language would have suited the early human lifestyle, Armstrong says. Groups of hunters could have used visual signs to communicate during a hunt without alerting their prey. It’s possible that gestures eventually became associated with sounds, which got more sophisticated as the human vocal tract evolved, Armstrong says.
Even now, there are close links between the brain centers involved in speech and those involved in sign language.