Fun fact: The term Lingua Franca originally meant something closer to Portuguese than the French spoken at the time. Eventually though, the French language did become the Lingua Franca truly, for some time.

Neither is pedantry a sign of intelligence, a message many a contributor to this here site would be good to take to heart. As to the choice of language English is and will most likely remain the lingua franca (pun intended) in most of Europe as it is the language which is most often learned as a second language. While many Europeans are not fluent in this language they do manage to read and make themselves understood in it. This makes it not a bad starting point just like the grandparent stated.

Basic fluency in English is widespread enough that I've had to be way out in the boonies in pretty much any country I've visited for me not to find somebody who can speak English. It makes me feel like a bit of a fool not being able to speak anything but English myself. I've got a learning disability that affects my ability to learn languages, so as much as I've tried, I'm not able to get much further than being able to get fed and find the bathroom in any other language.

I did hit a funny situation in rural France once where I was talking to a French restaurateur through one person who spoke French and Spanish, and then a second person who spoke Spanish and English. It was convoluted, but it worked enough to get me a meal. Alternatively, when I was in rural Spain, near the French border, a French speaking lady desperately tried to get me to help translate for her since she didn't speak Spanish and the merchant she wanted to talk to didn't speak French. Unfortunately, neither of them spoke English. The best I could do was communicate to the merchant in my broken Spanish that I couldn't help.