query: SELECT DISTINCT ?item ?itemLabel ?itemDescription ?iso ?glottolog
  WHERE {
      ?item wdt:P220 ?iso . # looking for language that has a ISO 639-3 code
      MINUS {?item rdf:type wdno:P1394 .} # without those with a « no value » Glottolog ID
      OPTIONAL {?item wdt:P1394 ?glottolog .} # show the Glottolog ID if it exists
      FILTER(NOT EXISTS {
        ?item schema:description ?description .
        FILTER(LANG(?itemDescription) = "en") # with missing description in English
      })
      SERVICE wikibase:label { bd:serviceParam wikibase:language "fr" ,"es", "ru", "de" } # show the label and descriptions in French, if it doesn't exist then in Spanish, then Russian, then German
  }
  ORDER BY ?itemLabel