public static function stem($word)
    {
        $nounStem = self::roughStem(
            $word, self::$_nounMay, self::$_nounPre, self::$_nounPost, 
            self::$_nounMaxPre, self::$_nounMaxPost, self::$_nounMinStem
        );
        $verbStem = self::roughStem(
            $word, self::$_verbMay, self::$_verbPre, self::$_verbPost, 
            self::$_verbMaxPre, self::$_verbMaxPost, self::$_verbMinStem
        );
        
        if (mb_strlen($nounStem, 'UTF-8') < mb_strlen($verbStem, 'UTF-8')) {
            $stem = $nounStem;
        } else {
            $stem = $verbStem;
        }
        
        return $stem;
    }