Similarly, D&D tends to handwave language translation issues. There is a "common tongue" that most folks are expected to speak. That also strikes me as a rather American point of view. Most Europeans that I've known have had experience with multiple languages, for example, and expect to sometimes have to overcome linguistic obstacles.
Actually, I don't think this qualifies as an "Americanism" or "Anglicism" or even "Eurocentricism."
Historically speaking, whenever you have a powerful "empire" with nearly global influence, you're going to have some kind of language that dominates trade and/or diplomacy and/or the sciences. This would be the "lingua franca" or "vehicular language"
Lingua franca - Wikipedia, the free encyclopedia
Currently, English of some sort is the dominant economic/political language...and German & Russian get a lot of play in engineering. Before that (say...pre WW1), the "lingua Franca" was actually French. Before that, it was Latin, and before it, Greek.
Further east, you'd probably find Chinese or one of the languages of India to be broadly spoken. Arabic filled this role as well.
In the pre-Columbian Americas, some languages spread as trade languages the same way.
And by that, I don't necessarily mean fluently. Sometimes, its a "pidgin" version of the language, with all kinds of bad syntax, verb/subject agreement, improper forms & noun genders. Foreign terms creep in. And there is more reliance on gestures.