2015-10-26 21:10 GMT+02:00 Michael Everson <everson@evertype.com>:
>
> “Basic English” is a well-defined language form, but “simple” is not. That’s one problem.

Here is the best definition I'm aware of:
https://simple.wikipedia.org/wiki/Wikipedia:How_to_write_Simple_English_pages

It's a mix of Basic English, VOA Special English, and some more guidelines, and like everything in Wikipedia it's not set in stone.

I guess that the Simple Enlgish Wikipeia is the only place where this set of rules is used. Can that be a problem? If it is, then maybe it can be something en-x-simple, although it's uglyish for a domain.
 
> I’m the IANA subtag registrar, if you didn’t know it.

I didn't!
 
> Maybe “wpsimple” would be precise enough. Are there other Simple Wikipedias?

Not at the moment. There is a certain possibility of this happening in the future.