It will never cease to be funny how inaccessible "a11y" is if you don't already know what it means. Mike Judge couldn't even make this stuff up.
(Lack of an obvious pronunciation is a good objection, tho.)
To this day I don't know what Eli8 means, and I'm not going to even bother to look it up. It's not communication.
I think where we differ is that I see such abbreviations as no worse than any other - TLAs (three letter acronyms) can also be as impenetrable.
My first guess would have been a username for somebody named Elliot. Given that it occurred in this thread, probably not a correct guess.
It's most pronounced in aye-ate-een-en, internationalization is a word I find myself stumbling when saying in full.
ally?