Today I looked up a T.V. Series that is involved with deaf people. The Switched at Birth cast came up, so I went to You-tube to try and see how or what helped them learn ASL better. One of the episodes they shot was completely in sign language, they had said that they took a big risk in doing so but it was worth it. Vanessa Marano (Bay's biological mother) has said that for this episode the directors have brought in more interpreters than usual in order for the deaf actors not to what is said to be done. Also, the way that they learn is from these people that are called in by the directors to only teach them their lines once a week.

 I looked this subject up just to see if i could learn sign language other than using you-tube.

http://www.backstage.com/advice-for-actors/backstage-experts/switched-birth-actors-talk-tvs-first-all-sign-language-episode-and-roles-deaf-actors/