"Good day is 'bon jour'", "thank you is 'merci'", and "the endings of most words are silent."
Trying to learn French on the fly was interesting. My volcabulary was very rudimentary: bon jour (good day), au revoir (bye), merci (thank you), parlez vous Anglais (do you know English), and most importantly vin (wine). I soon added other words: bon soir (good evening), Maxi Best of Royal Cheese (Quarter Pounder with Cheese Extra Value Meal for us yanks), sortie (exit), l' addition (the check please), and un, duex, trois, quatre, cinq (1,2,3,4,5).
The hardest part is learning their pronunciations. At first I thought they were just dropping the last letter. Our group was staying in Istres and another group was staying in Les Baux. Everybody pronounces Les Baux 'Le Bo'. Simple! Istres must be 'Istre', right? Nope. It's just 'Ist'. And up the road is Arles, pronounced 'Arl'. I modified my theory, the whole last half of the word is silent, right? It seemed to make since until one day when I was talking to Terry, a very nice English lady who managed the motel where our group stayed. We were trying to find places to tour and I mentioned Aix en Provence.
"Yeah, we went to 'I' en Provence."
"Umm... it's spelled A-I-X."
"They pronounce it 'X'. 'X' en Provence."
The easiest part was reading French. The French and English languages came from similar Latin roots and have influenced each other over a long period of time. There are many words that are only different by a few letters (mosquito - moustique), and there are also words that have crossed over between languages. With the constant commercialization American business is pumping into Europe, our language is becoming more common in theirs. Note above the 'Maxi Best of' meal. I successfully stopped a friend in need of a restroom from entering the employee only door at a QuickLunch (the french answer to invading McDonalds) by reading the sign.
Fortunately you do not need to know a lot of French to survive there. There is about a 50% chance there is someone nearby who knows English if you need help. If not you can usually get your point across by rephrasing what you say with different words. They might recognize a few of the words you say. I still don't know enough French to converse, but I'm pretty confident I can get by.