ASL is a visual gesture language. People use their eyes, body language, and hand gestures, to communicate. Failing to use one of these is not communicating. This can be compared to friends speaking Spanish. One is constantly talking and doesn't listen to his friend. They are not communicating very well. The same is true of signing gestures in sign language and not having any facial expression what so ever. That would be a boring conversation and one or both parties would not really understand whats going on. They failed to communicate. ASL is a unique language for those who cant hear. Some are born deaf, others loose their hearing at another time in their life. Regardless of how you loose your hearing, if you lost it this language is a huge benefit. It allows those who can hear anything to still speak. This language was founded in the 1800's. It was then when schools started teaching ASL and it really became popular.