string setlocale ( int $category , string $locale [, string $... ] )
Sets locale information.
Returns the new current locale, or FALSE if the locale functionality is not implemented on your platform, the specified locale does not exist or the category name is invalid. An invalid category name also causes a warning message. Category/locale names can be found in » RFC 1766 and » ISO 639. Different systems have different naming schemes for locales. Note: The return value of setlocale() depends on the system that PHP is running. It returns exactly what the system setlocale function returns.