In the video after the break you can see the concept being illustrated with playful examples that interact with the program, but more useful applications include the ability for users to pull up subtitles for public information videos, or overlay sign language.
Regarding language barriers, I try to use as few words as possible, and most of the ideas are expressed with the visuals so my videos are clear to people no matter what language they speak, and it held true with the Games We Play video.