Baby Sign Language Dictionary is a fantastic app.
It's important to mention that this app was designed for new parents to learn and teach American Sign Language to their babies who have not yet developed language skills. Studies show that children who are not yet able to speak may still be able to learn to communicate using sign language.
The fact that the app is so simple, that new parents and babies can use and learn from it, it stands to reason that any individual wanting to learn American Sign Language could begin their learning with it. This assumption is so true. I simply went through, beginning at the letter A, and watched video tutorials of the words that are contained in the app. I came out the other end knowing instinctively how to sign the words learned; it became a natural part of me.
This is because American Sign Language is largely based on symbolic gestures. For example, to sign the word apple you do a motion around the apple of your cheek. Or, to sign the word bad you basically make a motion with your hand that you might make if you tasted something bad and pushed it away from your mouth.
The instruction on this app emphasizes these ideas so that you not only learn how to sign the words and concepts, but are taught to understand why those are the hand signs for those words and those concepts. You get a clear understanding of the gesture and simply know it, because of course, that's how you would show it with your hands.
I highly recommend this app to not only the intended users (parents and children) but anyone who has an interest in learning American Sign Language.
Compatible with iPhone, iPod touch, and iPad.