The "gestural" origin of language in humans is supported by our research, which means that we most likely used gestures to communicate before we developed the neurological wiring and anatomy to produce speech. Gorillas have a complex communication system of their own involving gestures, postures, facial expression and vocalizations (if you watch them closely) and we have merely extended their vocabulary to include shared aspects of our gestural language so that they can communicate with humans (ie, American Sign Language).
Read more Read less
Penny teaches a young Koko the sign for "hear" using American Sign Language.
Photo by Ronald H. Cohn. Copyright © 2011 The Gorilla Foundation / Koko.org