TEI: Guidelines for Electronic Text Encoding and Interchange

<rng:element name="langKnown">
 <rng:ref name="att.global.attributes"/>
 <rng:ref name="att.global.analytic.attributes"/>
 <rng:ref name="att.global.change.attributes"/>
 <rng:ref name="att.global.facs.attributes"/>
 <rng:ref name="att.global.linking.attributes"/>
 <rng:ref name="att.global.rendition.attributes"/>
 <rng:ref name="att.global.responsibility.attributes"/>
 <rng:ref name="att.global.source.attributes"/>
 <rng:ref name="att.datable.attributes"/>
 <rng:ref name="att.datable.custom.attributes"/>
 <rng:ref name="att.datable.iso.attributes"/>
 <rng:ref name="att.datable.w3c.attributes"/>
 <rng:ref name="att.editLike.attributes"/>
 <rng:attribute name="tag">
 <rng:ref name="teidata.language"/>
 </rng:attribute>
 <rng:optional>
 <rng:attribute name="level">
  <rng:ref name="teidata.word"/>
 </rng:attribute>
 </rng:optional>
 <rng:ref name="macro.phraseSeq.limited"/>
</rng:element>

element langKnown
{
 att.global.attributes,
 att.global.analytic.attributes,
 att.global.change.attributes,
 att.global.facs.attributes,
 att.global.linking.attributes,
 att.global.rendition.attributes,
 att.global.responsibility.attributes,
 att.global.source.attributes,
 att.datable.attributes,
 att.datable.custom.attributes,
 att.datable.iso.attributes,
 att.datable.w3c.attributes,
 att.editLike.attributes,
 attribute tag { teidata.language },
 attribute level { teidata.word }?,
 macro.phraseSeq.limited
}