code: public void addLanguages( QueryParser firstLanguage,
                                QueryParser... additionalLanguages ) {
          addLanguage(firstLanguage);
          for (QueryParser language : additionalLanguages) {
              addLanguage(language);
          }
      }
docs: Add one or more languages to this engine by supplying the corresponding parsers.
  
  @param firstLanguage the query parser for the first language
  @param additionalLanguages the query parsers for the additional languages
  @throws IllegalArgumentException if the language parser is null