code: private static Set<String>  parseSystemLanguage(String val)
     {
        TextScanner      scan = new TextScanner(val);
        HashSet<String>  result = new HashSet<>();
  
        while (!scan.empty())
        {
           String language = scan.nextToken();
           int  hyphenPos = language.indexOf('-'); 
           if (hyphenPos != -1) {
              language = language.substring(0, hyphenPos);
           }
           // Get canonical version of language code in case it has changed (see the JavaDoc for Locale.getLanguage())
           language = new Locale(language, "", "").getLanguage();
           result.add(language);
           scan.skipWhitespace();
        }
        return result;
     }
docs: must be supported if we are to render this element