'xs:language without regional part': {|xml|| en |}. 'xs:language with regional part': {|xml|| en-US |}. 'xs:language with IANA registered language': {|xml|| i-navajo |}. 'xs:language with private, unregistered language': {|xml|| x-Newspeak |}. 'xs:language with multiple parts': {|xml|| any-value-with-short-parts |}. 'xs:language with too long part'(fail): {|xml|| longerThan8 |}. 'xs:language with empty value'(fail): {|xml|| |}.