Also Germany.
I learned english in school but only enough to be able to read it.
Once I started reading user submitted short stories (lile fan fics but different) my grammar really improved.
Nowadays the content I consume is basically 90% english based.

Just my capitalization and grammar structure sucks. Also my vocal skills as I have no one to talk to.

But: I really have to thank my last Grundschul and Realschul english teachers. Without those two I may have never got into english that well.

That's a point current generation children are actively working on by following English-speaking streamers, communicating in predominantly English Discords, etc. The worst: my kid chose to prefer American English. Where did I go wrong?

Of course I know people that only speak one language.

It’s me.

I don't know that it's necessarily that it's "inefficient". Moreso that it's difficult for a language to actually stick and be useful if you're not immersing yourself in that language. You can go to class all you want, but if you're not trying to actively immerse yourself in it beyond class, you're not going to learn the language no matter how good the teacher is.

It's relatively "easy" to immerse yourself in English language content because English has sort of become the "lingua Franca" of the modern world. Something like Polish, for example, isn't.

Same with French here in Canada. I took French for six years and I still don't speak it at all, and I actually did really well in my French classes.

It doesn't help that outside of school, you will never use that language. Even if you go abroad, everyone either wants to practice their English or thinks your French/German is so poor that they'd prefer to just speak English.

I took Spanish for three years here in the States. Most of the Spanish I know now I learned after high school. This seems to be a pretty common problem in nations with English as the official language...

and could barely speak a few basic sentences after 5 years of schooling

Thanks to events earlier last century pretty much everybody at least in Europe/Russia can speak a few basic sentences, and is often more than willing to demonstrate: "Haende hoch!" (hands up), "Nicht schiessen!" (don't shoot) and a few others.

Exactly. Unless things have changed dramatically, one or two years of a foreign language is a requirement in high school, and there are more opportunities in lower K-12 these days from what I hear. However, you're right that this is not especially helpful without some immersion, and the practice of trading your kids to a foreign family for a year is far less common. Then, after K-12, opportunities to practice greatly diminish.

The German mother of a good friend moved to the US West coast when she was a young adult, married, and had my friend. She never lost her German accent. When I was in my early 20s, I had the opportunity to live and work in Germany for a couple of years, and when I came back, I was fairly fluent - enough to pass as a native from a "different region." I visited my friend when I returned, and tried to have a conversation with her mother in German; she sadly informed me that she had forgotten most of her German, and could no longer converse... there are few opportunities to speak in German on the West coast, and even native language skills attrophy if unused.

In a related annecdote, when I first returned to the states, I'd sometime fail to remember the English words for the odd thing, like "trash can." All I could remember was the German word for it.

All thay has gone away. Years later, I can barely hold basic conversations in German. Maybe some people have an ability to retain language skills without practice, but I believe it's far more common to lose fluency you once had.

It also has to do with the wide diversity of languages spoken. The elementary school where my kids go put out a statement during the pandemic that there are 32 different languages spoken by kids at home. They had gotten many requests for school communications in more than just English and Spanish, and had to explain why that wasn't feasible.

So there are a ton of bilingual kids in their school, but my kids could learn the 4 additional languages spoken by the kids in their classroom, and the following year they would need to learn 4 entirely new languages. They learned to count to ten in several languages, but like you said, they will never have the opportunity to become fluent if they don't go somewhere less heterogenous.

Found the Brit/American/Australian? (Delete as appropriate)

I believe firmly that anyone can do it. You just need to find community and a good reason to keep going.

As in non swedish programmers try to translate into Sweedish for you?

you need to keep using it. Watch a show or read a book in that language every once in a while. It'll do wonders to keep the brain on it.

Keeping them separate is a struggle! Especially if they come from the same ancient language. I have troubles separating like German and English, and also Italian and French. Especially when I try to speak German, I end up throwing in lots of English words and structures