I downloaded the Speaky app from the Apple store to see what it does. It is currently free but may soon come at a small charge. It is one of a number of text-to-speech apps; others are reviewed here.
Essentially it is text-to-speech tool which reads out texts in very acceptable French. Lots of other languages are available. You can type in your own text, copy and paste text or just enter a URL for a site in French. Speaky recognises the language from the text and will give you pronunciation options ("standard" or Canadian French). In each case the text is read aloud for the user with the speed of delivery being adjustable. As is typical with text-to-speech tools the intonation is not entirely natural, but nor does it sound unacceptably artificial. The accent is excellent.
Who could use this? Well, I certainly had pupils who would write out text for their oral controlled assessment into text-to-speech sites so that they could practise by hearing a good spoken model. This does just the same, but in a rather more convenient fashion for iPad and iPhone. Teachers working with iPads might find use for this, especially if pupils have headphones for personal listening.
Other learners, for example adults doing continuing education, would also find use for the app in terms of improving their pronunciation, or helping them prepare for oral presentations.
In addition, teachers could produce listening exercises from approprate written texts. Just copy in the text, produce a comprehension worksheet and off you go!
Users who are blind or who have poor vision would also find such an app extremely useful and for this reason alone the app deserves a solid recommendation.
I would recommend it for teachers using iPads too. It comes with a few pages of simple tutorial. When I used it initially I got stuck as I did not spot the small cross at the top right of the "Let's get started" screen. You have to select this to start adding text. Maybe it could have been made more prominent.