I feel that you language that you speak greatly influences your culture and vise versa. Of coarse we are all human and created equal, but just look at someone who speaks Spanish from Mexico and then one that speaks English from the South US. Your going to see an instant difference every time you try to the experiment.
I believe that sign language is something that should never be forgotten or not learned by those who need it or just have the desire to learn it. It can be useful in many situations.