The language of the text in the element carrying this attribute. This is a mandatory attribute. The value UND (undefined) should be used if the language cannot be set for some reason. However, use of UND is discouraged by the W3 consortium.
Recommended or Prescribed Values
XML type xs:language. According to [http://www.w3.org/TR/xmlschema-2/], recommended values are defined by the following reference: H. Alvestrand, ed. RFC 3066: Tags for the Identification of Languages 1995. Available at: http://www.ietf.org/rfc/rfc3066.txt.