All sounds very similar to the way humans seem to pick up language, and change it.

On the train up to London from where I live there are all kinds of people from abroad, because we've git an international airport a few stations back, plus, of course, there are lots of foreigners living and working here.

So I find myself overhearing some foreign language, and trying to guess whether they're Russian or Polish or Dutch or whatever. Languages that I don't know.

But several times lately I've been doing that, and I suddenly realize they are talking English. I don't mean foreigners talking English in a foreign accent - I mean young English people, taking English in a way that didn't sound familiar till I listened and tuned into it, and I don't mean the vocabulary, but the sound, the music, you might say.

The relevance of that is that they didn't learn that from their parents or schools - like those young birds they picked it up from what they were hearing all around them.