I'm using Protege 4.3 to create my OWL2 ontologies. Recently i mentioned that when adding the annotation property rdfs:label you can choose to define a datatype (e.g. xsd:string) or a language (xml:lang). But it is impossible to define both. If you choose a datatype, the language field is faded and vice versa.
This could be a Protege specific problem, but i wonder if OWL2 itself prohibits the use of datatype and language at the same time. I did some research but I couldn't find any document where this is explicitly mentioned. But i also couldn't find an example where it is done. Something like ...
<Class rdf:about="MyClass">
<rdfs:label xml:lang="en" rdfs:Datatype="xsd:string">My special class</rdfs:label>
</Class>
... or ...
<http://example.org/AboutMe> ns0:gender "male"@en^^xsd:string .
I guess the above examples are not valid, but why?