query: #title: categories for films by language should be values of a statement with this property
  # Complex constraint from [[Property talk:P5996]]
  # TODO add P5996 to language item
  SELECT ?item ?itemLabel ?lg ?catLabel
  { 
      ?cat wdt:P971 wd:Q11424 ; wdt:P971 ?item . 
      ?item wdt:P305 ?lg .
      FILTER NOT EXISTS { ?item wdt:P5996 ?cat } 	
      SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
  }