Don't forget French though! I wouldn't make the assumption that travelling French people would have enough grasp of English or German to understand the announcements.
My comment is mostly a poke at the two assumptions: that non-English speaking countries should universally support English-speaking travellers, and that English is the predominant (and only other) language which should be supported.
We should be happy there is a language that has emerged for people to communicate globally without borders, and support it’s role as the worlds second language rather than work to re-fracture how people communicate
> "I’m baffled that any other language would be considered"
For local/regional trains, I wouldn't expect any language other than German.
For international trains, we should have all languages of all traversed countries and English. So for example a train from Paris to Frankfurt should have announcements in French, German and English (and it is actually the case for that train, I already rode it).
But for example, the Berlin - Warsaw train has only English announcements besides the local language depending on the country the train is in (so no Polish when it is in Germany, and no German when it is in Poland), I consider this to be wrong. It should have announcements in Polish, German and English for the whole route.
I seem to recall lines in Belgium that do announcements is 4 languages: french, Flemish, German, and English.