This is one of InLOC's direct properties.

In XML, this could be expressed through the usual "lang" or "xml:lang" attributes at the appropriate place in the documentation, in the normal ways. As well as an attribute of the root element (generally LOCstructure), an xml:lang attribute may be added to any other element whose value is a human-language string, in particular:

Language as a topic or subject is quite different, and should be documented through the appropriate LOCassociation of type: topic.

See also Multilinguality.