I am wondering if there are any languages that extend PHP into something ahem "better"?
They don't have to necessarily be able to interact with PHP, but it is certainly a benefit if they can (e.g. call PHP functions or even be called from PHP).
Here's an article from CodingHorror about Wasabi, a language which apparently compiles down to PHP among other strange things:
If you mean extending PHP's capabilities, I assume the plentiful modules that exist for it already do that...
The content is written by members of the stackoverflow.com community.
It is licensed under cc-wiki