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.