code: public String getLemma() {
        if (isInstance(Types.TOKEN)) {
           if (contains(Types.SPELLING_CORRECTION)) {
              return get(Types.SPELLING_CORRECTION).asString();
           }
           if (contains(Types.LEMMA)) {
              return get(Types.LEMMA).asString();
           }
           return toLowerCase();
        }
        return tokens()
                  .stream()
                  .map(HString::getLemma)
                  .collect(Collectors.joining(
                     getLanguage().usesWhitespace() ? " " : ""
                                             ));
     }
docs: Gets the lemmatized version of the HString. Lemmas of longer phrases are constructed from token lemmas.
  
  @return The lemmatized version of the HString.