Unrelated question, and not to pick on you if English isn't your first language - I'm always impressed by people who speak any multiple languages with any competency:

I've seen people misspelling flu as "flue" a lot over the course of this pandemic. I thought maybe that it was a British spelling, or that it was the word in German or French or Russian or something and foreign language speakers were mistakenly using the same word in English based on the similarity, but I can't find a language where that's the case. What's up with that?