[a_c_s]

I would actually argue that if a child and an adult spent the same amount of time engaged in language learning and were graded on the same metrics the adult would get farther. I don't think there's a magical cutoff where we suddenly can't learn languages anymore.

Rather, I think it is partly because we grade them on a curve that children are said to be amazing linguists

Children have many other advantages that also help them: * More free time * Fewer internal distractions (Did I lock the door? What am I making for dinner? etc.) * Not being afraid to make mistakes