English, (English, and English)
If you do speak other languages it is good to make sure you have them handy.
But learning a new language for the trip is not useful.
In all tourist areas in Europe they speak English, but of course, if you do speak the language of the country/area.
If you do not yet know the language of area, learn some social niceties, like good morning, thank you very much and good bye.
Use those with a smile and you will be seen as polite.
It's pretty easy to get around in English in the major tourists. Then it would be useful to know the language of the country where you stay the longest. Germany, Austria and parts of Switzerland and Italy are German Speaking
Much as I think everyone should learn other languages, I have to say that it's difficult to use another language in Europe, as most of them speak English better than we speak their languages. However, I found it very useful to know some Italian to read the road signs. "Peligroso" (danger) is a particularly good word to know.
English is really all you need, but a few words and phrases in the language of the country you're in can be very helpful too.
Of course, you could be fluent in any language you like, but if you don't have a positive attitude, a sense of humour, good manners and patience, fluency in any language won't help you.
First and foremost English, because most people speak it at least a bit, maybe not as their 1st language but as their 2nd or 3rd.
After that either German or French, as both cover a major country plus a few smaller ones.
English, German, French and (in the east) Russian. Spanish is gaining some popularity, but mainly among people who have an affinity with Spain.
If you know how to find the speakers, Esperanto can be quite useful too
French, German, and Italian are good languages to know.
well english,italian (only in italy) and german
American. We own the world, and they know it.
