They have some internal languages, too. Many Map-Reduce programs are written in Sawzall, named after a really nasty reciprocating power saw that will cut through ... anything. A Sawzall program reads one line of input and produces one line of output. Pretty cool stuff. Read any papers you can find on Map-Reduce and other Google innovations. Lots of amazing things happening there.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi