Making use of C++ to speed up PHP

Question

I saw this post on Sitepoint quoting a statement by Rasmus Lerdorf which goes (according to Sitepoint) as follows:

How can you make PHP fast? Well, yo

Answer 1

Thanks to Artyom for the link to this informative link,

http://idleprocess.wordpress.com/2009/11/24/presentation-summary-high-performance-at-massive-scale-lessons-learned-at-facebook/

which says, among much else, "C++ Interoperability Challenging."

C++ requires much effort to write a website. Why not pick a language between C++ and PHP, say Python which is executed by bytecode JIT, and I understand is relatively easily extended by C++.