It really seems to me you are implying they can't read regular English - doesn't that make regular life quite a challenge? I would have assumed learning written English would be high priority.
Your answer just makes me even more confused. If they can't read English, what is the computer translating the sign language into? What are they doing with the results?
And this just brings up even more questions - how do they speak remotely to people? I was thinking that a video phone was an amazing advance, except you'd have to put the phone several feet away from you, making it pretty hard to see the screen.
Every single scenario I'm thinking of just makes the need for written language even more critical - otherwise such a person is almost entirely isolated, except when near other signing people.