People born deaf can learn how to listen to what another person simply by watching the movements of their mouth and facial expressions. The aptitude to learn such communication is hardwired into the human brain. It is one of the most important survival skills humans have ever evolved, as a social species. It is why we see faces in the clouds, faces in tree trunks, or the face of Christ in a grilled cheese sandwich. Notice that nobody ever sees the hand of Christ, or the cunt of the Virgin Mary, or even the back of the head of Moses, appearing in anything. They face is the most important factor in human communication, and it always has been. And half of it was gone for developing children for over two years.