This meme has been around for at least a hundred years as I remember my father talking about it in the early fifties
creationism was strong and it was hoped the children wd suddenly start using Aramaic of ancient Hebrew - Babel and all that.
They didnt
Napoleon's son ( Napoleon II) was said to be brought without books and tutors as they were afraid he wd turn out like his father. IF you read the wiki article, this wasnt so
AND - lastly - Nicaraguan Sign Language was purposely allowed to develop ( "the first time we see a language being born" the voice over gushingly describes) without intervention.
https://en.wikipedia.org/wiki/Nicaraguan_Sign_Language
Heavily criticised as being NOT in the interests of the deaf of Niacaragua ( they cd have used Spanish SL) but to provide fodder for papers and publications of the authors. This consideration should not have entered the equation at all