[asuth]

We decided the most realistic audio came from commercial vendors.

In terms of mobile stuff, we've thought about doing our own but for now there are great apps being built on our API. We just launched V2 of our API with OAuth integration: http://quizlet.com/blog/quizlet-announces-api-2/

If anyone's interested in building mobile stuff, feel free to play around with it. Or contact us (email in profile) and we may have a job for you :)