!!!THIS SCHEMA DOCUMENT IS OUT OF DATE!!! It uses a preliminary W3C XML Schema syntax which has been superseded. The up-to-date version is at http://www.w3.org/2001/xml.xsd This schema defines attribute groups suitable for use by schemas wishing to allow xml:lang or xml:space attributes on elements they define. To enable this, such a schema must first declare the XML namespace, and then import this schema for the XML namespace, e.g. as follows: <schema . . . xmlns:xml="http://www.w3.org/XML/1998/namespace"> . . . <import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/XML/1998/xml.xsd"/> Subsequently, qualified reference to either of the attribute groups defined below will have the desired effect, e.g. <type . . .> . . . <attributeGroup ref="xml:lang"/> will define a type which will schema-validate a instance element with an xml:lang attribute In due course, we should install the relevant ISO 2- and 3-letter codes as the enumerated possible values . . .