code: public static function pluralize($word)
      {
          if (isset(static::$specials[$word])) {
              return static::$specials[$word];
          }
          foreach (static::$plurals as $rule => $replacement) {
              if (preg_match($rule, $word)) {
                  return preg_replace($rule, $replacement, $word);
              }
          }
  
          return $word;
      }
docs: Converts a word to its plural form.
  Note that this is for English only!
  For example, 'apple' will become 'apples', and 'child' will become 'children'.
  @param string $word the word to be pluralized
  @return string the pluralized word