And this is an entirely unscientific assertion, but perhaps this is why I had never heard of Alzheimer's while in India. Everybody there is at least bilingual. And if an Indian knew English, Hindi and a South Indian language, they would know languages from three linguistic families with completely different morphology and syntax.
I was reminded of all this when I saw an out-of-office autoreply from a person on one of the mailing lists I'm subscribed to. This is in French, and I did attend a semester of French at college, but I would think any English speaker could decipher this using the "neural pathways" they already have:
et merci de votre message.
Je suis absent du bureau avec peu de d'accès à ma messagerie.
Je prendrai connaissance de votre message à mon retour dès le 10 octobre.
En cas d'urgence, vous pouvez contacter M. _____ ( email address ).
Bien à vous
A few familiar words (if spelt slightly differently) and a well-understood context, and the message becomes completely comprehensible. Even the "Bien à vous" sign-off seems to translate to the Aussie "Good on ya" (though it probably doesn't mean the same thing!)
As Mr Spock would say, fascinating.