I turned the volume on my iPad all the way down, but the app voice was still very loud. Id be unlikely to use the app in public because of this.
I had no other problems with the voice function. It worked every time.
If this little app crashes your iPhone then synch it with a desktop computer, update the OS and delete some of the junk apps on it.
Gunthar B about Bon appétit - French food and drink glossary