It's bon appetit and don't say the "t" at the end. Also, between the first course and the second when they lay down the plate for your main, it's "bonne continuation".
Honestly we don't bother expressing it that way, because sometimes they charge you a fee for an extra plate. One of us orders the salad (or dessert) and then we share.
I've never thought of Neuchâtel as being cheap but it clearly is in comparison to other places.
Definitely not vegetarian, there are two meat loving males in the family one of whom also a one man teenage eating machine with a very large appetite.
We have never even paid close to 100chf per person here in a mid range restaurant here for the type if meal you describe and your salad, wine and coffee lunch wouldn't be more than 30chf.
Agree with the others about sharing without mentioning it. Also worth pointing out that while sharing a starter, salad, or dessert isn't so unusual, sharing a main course is strictly frowned upon.
Sounds fair, except the waiter might just stand there and ask the other person what they want, expecting that each of us will have an entree (or dessert).
Back in Australia, between friends it wasn't unusual for us to order different dishes for each course, then offer to try a bit of each one (we didn't split it in half, but just offer each a taste). It certainly wasn't unusual to split the entree (in fact, an option for a "share plate" entree was quite commonplace, and no we are not just talking about a Greek/Lebanese platter or Italian antipasti). I hear that can be viewed as rather unusual here (or in Europe, or...)
That's why we always just tell them and get the extra plate, it's nicer to have your own plate to eat from anyway rather than both eating from the same one.
You can share an entree here no problem. If you try to split a plat, they are not going to understand. Well, they might understand, but they are not going to be happy.
In my experience here, the server asks each person what they want in turn, so there's not much confusion. It might go like this:
Server looking at me: For you, Madame?
Me in reply: I'll have a mixed salad and the pizza margherita.
Server turns to OH: For you, Monsieur?
Him in reply: I'll have the pizza diavola.
When the food comes, we share anyway. At dessert/coffee time, we often just have one person order. So maybe hubby says "two coffees and one chocolate torte."
As someone else already pointed out, servers here are trained professionals - not clueless college kids scraping by. Don't overthink it. Also don't freak out too much about the language. As long as you try to speak French, the servers will appreciate it and many will switch to English in order to make you more comfortable.
Don't get me wrong - most servers here are not exactly friendly . They are sort of detached and professional, which often comes off to an American as being cold and rude.
I think it depends on the restaurant and the time. Obviosuly if somebody occupies a table at mealtime, only orders a coffee and stays for two hours reading a newspaper and leaves only a miserly tip, that person will not be looked on kindly. Do the same in between meals and they'll probably be happy the restaurant isn't totally empty.
Likewise, if there's a queue of people outside, four adults occupying a table and sharing the cheapest dessert is not going down well. If the restaurant is half empty on the other hand, it's better for them to have that than to have nothing at all.
A little bit of situational awareness can go a long way.
In the same way that many Europeans don't feel comfortable with American waiters as they find them much too touchy, feely, unrefined and familar. Most Europeans don't want the waiter to introduce themselves by name and don't want to be asked how they're feeling today. Way too personal and unprofessional.