id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
20291	"html element ""lang"" bug"	ricardojvcruz	ricardojvcruz	"Wordpress core function ""language_attributes()"" is returning by example 'en_US' and should return 'en-US'.
This could be important when crawlers are parsing and indexing pages saving the parsed language found in that element.

Following w3c specification of html language attribute we can confirm that.

HTML 4.0 lang spec:
http://www.w3.org/TR/html4/struct/dirlang.html

HTML 4.1 lang spec:
http://www.w3.org/TR/html401/struct/dirlang.html#adef-lang

HTML 5 lang spec:
http://dev.w3.org/html5/html-author/#the-html-element"	defect (bug)	closed	normal		I18N	3.3.1	normal	invalid	has-patch	info@…