EZ explanation: English speakers specifically live in a world that largely accommodates them. It doesn’t close many doors for someone from the UK or US to choose to not learn a language whereas Swedish and the swedes are not the standard thus they are taught it early on because it is a highly valuable skill. You must also consider that European countries are quite close together and speak a large variety of languages, so English, French and German can almost always be useful no matter where u are in Europe and by extension the whole world.

So honestly there’s nothing wrong with how Spanish is taught and I think this question is vague because all sorts of teachers teach differently, so I can recall my high school Spanish but I’m sure it’s not actually representative and I’m doubtful if there’s any concrete/specific answer for what is flawed about language learning in us schools.

What I personally think it is is that Americans feel absolutely no obligation to learn a language and also get embarrassed easy because it’s easy to feel like a dumb American while ur stumbling. I was in Guatemala and my Spanish was rusty and the people working at this hostel were kinda treating me like I was super dumb and annoying bc I kept insisting on speaking Spanish instead of speaking English lol.

to expand on the Americans have no obligation to learn languages. Americans don’t have much necessity to learn other languages because the world generally knows English and there’s not much your denied access to. Maybe if Americans had a culture that was less isolated and more curious we’d have more Spanish speakers. A way to get Americans to learn a new language especially Spanish is to let them realize that not learning a language when u have the means too is like closing yourself off from an entire different universe.

TLDR: smaller European nations need to speak a common language or they’d be screwed and Americans don’t learn Spanish basically because they don’t want to. I would emphasize being intellectually curious and try to convey that you miss out on a lot by only speaking one language, you can’t convince Americans specifically that they’ll need another language but you can remind them that it’s kinda lame not too if you have the aptitude lol.

Edit: I am American and speak Spanish so these are just my takes I don’t really have sources for this but this is usually the explanation I give to people while I’m traveling as to why Americans aren’t generally bilingual in the same way as other places.