I watch one season of some show in a language I don’t understand
I wish my brain worked that way; I’d be watching Finnish television and movies all day, every day.
I watch a fair number of shows in Swedish or Norwegian, and I’ve never picked up anything from what they’re saying. I always have to have subtitles.
It’s been years since I had glög; I should make that again since it’s starting to get chilly.
Unfortunately, part of living in the US is that most people aren’t exposed to other languages to any significant degree. If you are a native American English speaker, and grow up in a large city, you might hear enough Spanish to learn it, but that’s about it. I learned Spanish in school, but there was no opportunity to practice until I moved to a large city close to the Mexican border.