How can a handheld/portable device assist the Deaf and hard-of-hearing community in better communicating with and understanding hearing people, and thus supplementing or reducing the need for hearing aids or interpreters?

ASL and English are two different languages. How can I bridge that gap visually, through a user experience? That line of thinking alone excites the designer in me. This is gonna be awesome.

Also, a little relevant find & share: http://www.youtube.com/watch?v=sjln9OMOw-0