Default language ignores Path prefix

I want to have 2 languages: English [en] and Bulgarian [bg], with both using path prefixes. The problem is that whatever default language I set ("bg" or "en"), it doesn't add path prefix to URLs. (I've changed English to have "en" path prefix.) The cause of the problem seems to be the following lines in includes/language.inc:

      case LANGUAGE_NEGOTIATION_PATH_DEFAULT:
        $default = language_default();
        if ($options['language']->language == $default->language) {
          break;
        }
        // Intentionally no break here.

      case LANGUAGE_NEGOTIATION_PATH:
        if (!empty($options['language']->prefix)) {
          $options['prefix'] = $options['language']->prefix .'/';
        }
        break;

So if we have default language and LANGUAGE_NEGOTIATION_PATH_DEFAULT, no path prefix is added. This if...break surely is there for some reason but commenting the break fixes my problem.