query: SELECT ?firstLetter (COUNT(?lemma) AS ?count ) WHERE {
    ?lexeme a ontolex:LexicalEntry ; dct:language ?language ; wikibase:lemma ?lemma .
    ?language wdt:P218 'cs' .
    BIND ( SUBSTR(UCASE(STR(?lemma)), 1, 1) AS ?firstLetter )
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],cs". }
  }
  GROUP BY ?firstLetter
  ORDER BY ASC(?firstLetter)