But the apps that have turned the iPhone into a more useful tool -- be it as simple as a flashlight or as sophisticated as a languagetranslator -- have been relatively rare.
This gives an idea of the power available to anyone who wished to develop something like a translator for sign language, or a way of studying motion to develop physical therapy strategies.
She spoke a pre-Inca language, Aymara, and through a translator I learned that she was explaining her success at feeding her kids for the first time in her life.
That possibility inspired Ms. Dai, the translator, an associate professor and vice dean of the department of Chinese language and literature at Fudan University in Shanghai.