Quality of education. You're far from the only American I've heard say: I took x years of y and can't even say 'hi' in y.
I don't know what American schools do wrong, but Europeans have little trouble teaching kids to have a working knowledge of foreign languages in the same number of years.
The brute force approach would be to live in a place where the language you're trying to learn is native. English is my 3rd language but I didn't get really fluent in it until moving to the US.
There's are other factors besides schools between American students and European students. For many Americans, the reality of ever needing to speak any language but English seems totally theoretical, whether for travel, business, or profession. For many Europeans, needing to speak a non-native language appears much more realistic. Further complicating this is that if one's native language is English, then it DOES work almost all the time, reinforcing the notion that foreign languages are merely decorative. By contrast, if you were a Dutch computer scientist like Dijkstra, you would understand very early that you could never hope to write professional papers in Dutch. (Brits have the advantage of seeing that other languages really are used, but share the disadvantage of already being fluent in what is nearly a world language.)
I don't know what American schools do wrong, but Europeans have little trouble teaching kids to have a working knowledge of foreign languages in the same number of years.
The brute force approach would be to live in a place where the language you're trying to learn is native. English is my 3rd language but I didn't get really fluent in it until moving to the US.