Is it difficult if it’s also inevitable? In a social setting, a child will either learn a language or develop one — two wild children would develop a rudimentary language that would evolve in complexity as it’s passed down generation by generation. I wonder if a feral child, who matured alone and without social interaction, could learn a language later in life. Or, if it could, how difficult it would be.
What do you mean by the critical period in learning being a byproduct of learning over time as opposed to a special feature of the brain’s age? I don’t think I grasp it. Are you saying that it’s not really the brain’s age, but rather that it hasn’t learned a lot yet? Which are distinct but highly correlated.
A large foundation for the belief in critical periods for language are based on Genie, a feral child who was entirely unable to learn a spoken language despite significant efforts. Today, she can use some sign language but cannot speak.
https://en.m.wikipedia.org/wiki/Genie_(feral_child)
So the answer is largely believed to be: No. You cannot learn a spoken language if you missed the critical period.
It’s also literally impossible to test/study ethically, so nobody actually knows.
Just from the overview of that wikipedia page, it’s clear she has been subjected to a horrific amount of abuse and emotional turmoil, both as a child and later as an adult. It seems extremely dubious whether you can really draw any general conclusions from such an extreme case study.
How could a child not be exposed to any spoken language without that circumstance also being somewhat traumatic?
I don’t have a source handy, but from what I remember: yes, a feral child can learn language later, but never to the same level of fluency. It’s more like learning a second language. Also there is extremely limited data because it mostly comes from horrifically abusive situations.
If I remember right, the most interesting data came from a study that gathered deaf children from areas where they had no sign language. The young children rapidly developed sign language, but the older children (teens) had a hard time keeping up and did not reach the same fluency.