public static function rules($type, $config = []) {
		$var = '_' . $type;

		if (!isset(static::${$var})) {
			return null;
		}
		if (empty($config)) {
			return static::${$var};
		}
		switch ($type) {
			case 'transliteration':
				$_config = [];

				foreach ($config as $key => $val) {
					if ($key[0] !== '/') {
						$key = '/' . join('|', array_filter(preg_split('//u', $key))) . '/';
					}
					$_config[$key] = $val;
				}
				static::$_transliteration = array_merge(
					$_config, static::$_transliteration, $_config
				);
			break;
			case 'uninflected':
				static::$_uninflected = array_merge(static::$_uninflected, (array) $config);
				static::$_plural['regexUninflected'] = null;
				static::$_singular['regexUninflected'] = null;

				foreach ((array) $config as $word) {
					unset(static::$_singularized[$word], static::$_pluralized[$word]);
				}
			break;
			case 'singular':
			case 'plural':
				if (isset(static::${$var}[key($config)])) {
					foreach ($config as $rType => $set) {
						static::${$var}[$rType] = array_merge($set, static::${$var}[$rType], $set);

						if ($rType === 'irregular') {
							$swap = ($type === 'singular' ? '_plural' : '_singular');
							static::${$swap}[$rType] = array_flip(static::${$var}[$rType]);
						}
					}
				} else {
					static::${$var}['rules'] = array_merge(
						$config, static::${$var}['rules'], $config
					);
				}
			break;
		}
	}