Assertion: When an xml:lang attribute and a lang attribute on the same element have different values, the xml:lang value will match pages served as application/xhtml+xml, and the lang value will match pages served as text/html.

Notes:
You can only get meaningful results for this test if :lang works with both lang and xml:lang attributes. If :lang does not work with xml:lang, the test should show a message "Ignore this test." You should ignore the instructions and test results that follow and mark the results as "not applicable".