<xs:attributeGroup name="i18n">
    <xs:annotation>
        <xs:documentation>
      internationalization attributes
      lang        language code (backwards compatible)
      xml:lang    language code (as per XML 1.0 spec)
      dir         direction for weak/neutral text
      </xs:documentation>
    </xs:annotation>
    <xs:attribute name="lang" type="LanguageCode" />
    <xs:attribute ref="xml:lang" />
    <xs:attribute name="dir">
        <xs:simpleType>
            <xs:restriction base="xs:token">
                <xs:enumeration value="ltr" />
                <xs:enumeration value="rtl" />
            </xs:restriction>
        </xs:simpleType>
    </xs:attribute>
</xs:attributeGroup>