declaring language in html/xhtml

My site serves some html and some xhtml [as text/html].

For convenience, I want to declare the language the same way for both types 
of content.

Does it make any practical difference to serve html with the html tag 
marked-up as xhtml, like:
<html lang="ja-JP" xml:lang="ja_JP"  xmlns="http://www.w3.org/1999/xhtml">

as opposed to simply
<html lang="ja-JP"> ?


thank you in advance.

Al.

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Received on Monday, 29 November 2004 18:26:52 UTC