The xml:lang attribute specifies the language of the content of the element that it is associated with. It is most often associated with the langSet element, to specify the language of all the child elements in a language section. However, it can be associated with virtually any element to specify the language of the content of that element.

Use the values found for “language” in the IANA language subtag registry. Do not use deprecated values. Do not combine script and region values with the language value; use the separate script attribute, and the geographicalUsage element.