Question: Which languages are spoken in Estonia?
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX res:  <http://dbpedia.org/resource/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT DISTINCT ?uri ?string 
WHERE { 
      { res:Estonia onto:language ?uri . } 
      UNION 
      { ?uri onto:spokenIn res:Estonia . }
      OPTIONAL { ?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
}