English is well on the way to being a default language. It has the most speakers of any language (Chinese has more native speaker). In Europe, almost 90% of kids in countries where English is not the main language study English as a second language.

Among adults in Europe, I believe that in every country where English is not the main language at least half the adults speak it as a second language.

English is the standard for aviation and maritime use, by treaty. It's also the de facto standard in computing and most of science. If one is going to deal internationally, and is only going to know one language, English is the best choice.