really! never knew that bevc. this year i am supposed to be learning a special sign language (with only one hand) because one of my best friends is quite ill and has now lost her speach because of it. she has a special computer thing that talks for her but can be unrealible. but as we have been friends since year 7, she spells letters with her hands(which only me and a few teachers can understand) but we are hoping to get someone in to train us a proper way of signing.
Think that signing with 1 hand would be quite difficult but I've seen students doing that - like a 'shorthand' version so to speak. Good luck with it! Bet your friend is very grateful that you've stuck around and supported her.