I'm thrilled with the app for iOS 7. Well done, developers.

There is a slight bug with the sound. It happens when you finish a voice translation / recorded pronunciation and "Check" it.

When the app says "You are correct" and shows the "Continue" button and the green checkmark -- all of that works fine, as normal. But it plays the "Incorrect" (wrong) sound.

This ONLY happens when using headphones on the iPhone 5S. And it only happens about 50% of the time (using headphones). Hope that is specific and helpful!