How does it only take a year or so to speak/understand our first language but it’s so much harder to acquire another language?

Question

Like, we have a frame of reference (first language), so why is it so hard to learn another language after that?

In: Other

Answer 1

If you spend every waking moment for ~three years straight in a total language immersion course, including one or more personal tutors who’ll spend hours a day working with you on everything from basic sounds to sentence structure you’ll be able to speak that language pretty damn well.

This is the environment most people learn their first language in. It’s a lot of work, but they have few responsibilities distracting them from it.