[Pyromaniac]

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Anyway, they alternate between english and spanish from one sentence to the next a lot of the time.


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Probably an obscure reference, but Nabokov's Ada or Ardor: A Family Chronicle explores this quite a bit, as I recall, discussing siblings who grow up *tri*lingual and who are able to switch mid-stream from one language to another to another. And understand each other perfectly while anyone listening is probably lost.

Wiki also lists this book with the tag "Category: Incest in Fiction", but that's another story. So to speak.

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In my experience with language, I've seen where the second language bleeds into any later language learning. So if you learn some French or Spanish in high school, then later learn something of another language, the French/Spanish will bleed into the third language.

But not the first language; you never start popping in English words--or at least without knowing it. So often struggling with limited vocab you throw in the English word and hope for the best...

It's as if there's an area in the brain that's first-language reserved, and then another area for all-other-languages. The two areas don't mix, but whatever's in them, does. And people who grow up with several languages have them all mixed together (but in the first area rather than the second).