People who cannot speak or hear can talk by using sign language.

不能讲话或听不见的人可以用手语交谈。

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These devices seek to move beyond the mouse and physical keyboard, letting people communicate with their gadgets by gesturing, using sign language or, in the case of Skinput, tapping on their hands, fingers and forearms.

CNN: Microsoft's Skinput turns hands, arms into buttons

Tuesday's episode, which coincides with Learn To Sign Week, features a storyline using deaf characters - both of whom are played by deaf actors - together with a hearing actor who uses British Sign Language.

BBC: Ben Crystal and Sarah Beauvoisin show off their skills