Count all the ethinic group who speaks language which belongs to Anglo-Frisian language family?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/ontology/languageFamily> <http://dbpedia.org/resource/Anglo-Frisian_languages> . ?uri <http://dbpedia.org/property/languages> ?x  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/EthnicGroup>}
Anglo-Frisian_languages