Make the very best set of reservations you can before leaving home. When you get to Paris and you still haven't a gotten a Frenchies' reservation, walk over during serving time and ask if he has anything available during your stay. Take whatever he offers and bag the runner up. That's what I do.
One eager guy reported here that he had his hotel send someone over to grab a reservation. That's a REAL chowhound!
1. You can't leave a message.
2. Once you get someone on the phone, yes he/she speaks English.
3. They do answer the phone. I literally caught them a week ago. It is best to call shortly before and after mealtime, such as within 30 minutes before and after. Such is my experience.