I've experienced this a lot (with myself, but especially with some hyperpolyglot friends who are or have been conversational in over 7 languages), and I'm kind

I've experienced this a lot (with myself, but especially with some hyperpolyglot friends who are or have been conversational in over 7 languages), and I'm kind of curious which way the causality runs! My intuition is to believe myself and others when we say that "knowing about more ways things can work" in languages makes it smoother to learn and assimilate new ones. But I also wonder if there could be an effect of "people who enjoy learning languages enjoy learning languages"?