http://code.google.com/p/html5lib/issues/detail?id=154

Reported by@fantasai, Jun 1, 2010

What steps will reproduce the problem?
Try to reserialize a document containing xml:lang

What is the expected output? What do you see instead?
For HTML output, I'd expect to getlang= in place ofxml:lang=.
Instead I get{http://www.w3.org/XML/1998/namespace}lang which
is completely malformed.