If you correctly ask "may I have a caramel" the correct reply is, "yes, you
may."
The CORRECT answer is "NO, they'll ruin your teeth and besides, I just
had the last one".

In American English, "can" is often used as a permission rather than
ability, and not just by people under 20. It's in common usage.

When I was a boy, there was a mother down the street who was a little
snooty and when her son asked "Can I have a glass of milk?", she would
reply "You can but you mayn't". Talk about losing the battle and the war.

I'd be surprised today if this now-grown man EVER used the word "mayn't"
and probably still uses "can" as a permission.

Such is language.

The idea of a new language / alphabet based upon internet texting IS
fascinating. Another poster is correct, it all started with hams'
abbreviations in CW.

Is there perhaps an earlier precedent?