if (preg_match('/(.*?(?:\\b|_))(' . self::$_singular['cacheIrregular'] . ')$/i', $word, $regs)) {
            self::$_cache['singularize'][$word] = $regs[1] .
                substr($regs[2], 0, 1) .
                substr(self::$_singular['merged']['irregular'][strtolower($regs[2])], 1);
            return self::$_cache['singularize'][$word];