Great idea. I don't know much about sign language but I believe that the US version is different from the British version, which is no doubt different from the French version and so on. In fact there may be hundreds of different versions to contend with. That aside, I believe that taking any single version (British for instance) there are signs for individual letters and other signs for complete words, maybe even phrases or abstract concepts. Let's say there are 100 different signs in total, then to animate the transition from one sign to any other would need 10,000 different animations (100x100). This may make the concept unworkable and may be why the people who've done it before use only flash images with no transistions. I'd like to think I'm wrong, but equally I'd hate somebody to start such a worthwhile project in a fit of enthusiasm, only to get bogged down by the sheer magnitude of the task. Somebody please prove me wrong.