title: OWL rdfs:langString and restricting its allowed languages
body: <p>Is it possible in OWL to restrict a Property with a range like</p>
  
  <pre><code>demo:property rdfs:range rdf:langString
  </code></pre>
  
  <p>so that we only allow "en" and "de" as languages?</p>
  
  <p>So </p>
  
  <pre><code>demo:object demo:property "hello"@en
  </code></pre>
  
  <p>would be allowed, but</p>
  
  <pre><code>demo:object demo:property "bonjour"@fr
  </code></pre>
  
  <p>would not.</p>