Translating sign languages to spoken languages is really, really hard. Sign languages have a lot of features that don't really show up in spoken languages. Let

Translating sign languages to spoken languages is really, really hard. Sign languages have a lot of features that don't really show up in spoken languages. Let's take an example: the sign for "send email" in ASL (http://www.lifeprint.com/asl101/pages-signs/e/email.htm http://www.lifeprint.com/asl101/pages-signs/e/email.htm). If I point at you at the end of the sign it could mean "I will send you an email." If I point at myself it could mean "You should send me an email" or "Did you send me an email" depending on my facial expression. If I point off into space it could mean "I'm sending an email." If I start by pointing at you and then end the sign by pointing off into space it could mean "You should send an email." So your translator AI needs not only to understand the facial expressions and movements of the signer, but also the spacial relationships of everyone in the conversation. And that is just one aspect of the difficulty - there are many other features of sign languages that are just as hard to translate. Perhaps this is the sort of thing that future AI systems could do. But it is quite complex.