A few months ago when I went to go hang out with my one (half Sudanese) (half British) friend, her (American) husband, her new baby, and her young daughter, she had told her daughter the day before that "[my name]" would be visiting, and right away her daughter was like, "You mean [my name] from the book?", since, as it turns out, her favorite book is about this little boy who's always breaking all the rules, in ways that are lavishly illustrated.
(Her dad, my friend's [American] husband, totally thinks that the appeal is looking at another child violate all the rules.)
So, my friend was like, "No, the real [my name] is coming!", and after that, her daughter was always like, "When is the real [my name] coming?"
Anyhow, we all hung out and her daughter showed me her little book, and I read the short sentences on each page to her and told her that I hoped that she never behaved like that.
"He's naughty," she would be like, and, oddly enough, when she said that, the main vowel in the word "naughty" was pronounced like the (British) do, but only that one vowel.
It was very odd to hear the first few times, but it was total child language acquisition in action, where her brain was presented with variants in the speech around her and she subconsciously selected one to incorporate into the way she talks.
I basically have read that over a few generations that's like how Australia happened, and New Zealand too, and there it was in front of me.