Ive been studying ASL on and off for 6 years, and my worst area has always been fingerspelling and reading letters quickly. Using this app and practicing the words after I answer them has improved my fingerspelling and comprehension significantly in just a few weeks. 20 minutes in the app every day or two is all it takes, and the speed setting and extensive vocabulary make it easy to adjust the app to your skill level. Fingerspelling is such an important skill to have in ASL, and the only way to improve is with regular practice, which makes this app an essential for anyone whos serious about learning the language.
Haslotsofapps about ASL: Fingerspelling (Lifeprint.com), v2.0.1