Duolingo has klingon, valerian and latin. But it does not teach sign language. Why not? My father (who has profound hearing loss) was not taught sign language, and when I tried to learn it for myself, I found that Duolingo values made up or dead languages over a language that should be accessible to everyone. I want them to include sign language in their classes so everyone can learn it, and make the world more accessible for those with hearing loss.