i18nAttributes 

A group of attributes for language and script related information

Attribute Group Information

Attributes

QName Type Fixed Default Use Inheritable Annotation
dir restriction of xs:NMTOKEN optional 
The directionality of textual content (enumeration: ltr, rtl)
xml:lang union of(xs:language, restriction of xs:string) optional 
Attempting to install the relevant ISO 2- and 3-letter
         codes as the enumerated possible values is probably never
         going to be a realistic possibility.  See
         RFC 3066 at http://www.ietf.org/rfc/rfc3066.txt and the IANA registry
         at http://www.iana.org/assignments/lang-tag-apps.htm for
         further information.

         The union allows for the 'un-declaration' of xml:lang with
         the empty string.

Used By

Elements a, bag, concept, contentSet/inlineData, contentSet/inlineXML, groupSet/group, inline, ruby, span
Complex Types AnyItemType, AssertType, BlockType, ContentMetadataAcDType, ContentMetadataAfDType, ContentMetadataCatType, ContentMetadataType, Flex1PropType, Flex1RolePropType, FlexGeoAreaPropType, FlexLocationPropType, FlexOrganisationPropType, FlexPOIPropType, FlexPartyPropType, FlexPersonPropType, FlexProp2Type, FlexPropType, IntlStringType, IntlStringType2, ItemMetadataType, Label1Type, Link1Type, QualPropType, RightsInfoType, partMetaPropType

Source 

<xs:attributeGroup name="i18nAttributes">
  <xs:annotation>
    <xs:documentation>A group of attributes for language and script related information</xs:documentation>
  </xs:annotation>
  <xs:attribute ref="xml:lang" use="optional">
    <xs:annotation>
      <xs:documentation>Specifies the language of this property and potentially all descendant properties. xml:lang values of descendant properties override this value. Values are determined by Internet BCP 47.</xs:documentation>
    </xs:annotation>
  </xs:attribute>
  <xs:attribute name="dir" use="optional">
    <xs:annotation>
      <xs:documentation>The directionality of textual content (enumeration: ltr, rtl)</xs:documentation>
    </xs:annotation>
    <xs:simpleType>
      <xs:restriction base="xs:NMTOKEN">
        <xs:enumeration value="ltr"/>
        <xs:enumeration value="rtl"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:attribute>
</xs:attributeGroup>