Question: What languages are spoken in Estonia?
SPARQL query:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri ?string
WHERE 
{ 
      ?country rdf:type onto:Country.
      { ?country onto:language ?uri . } 
      UNION 
      { ?uri onto:spokenIn ?country . }
      FILTER (regex(?country, 'Estonia')).
      OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
}