setLocale() doesn't change the language set by browser

Thank you but it's still not working.....
Checking with $language->getLocale() I see it's changing but in the lang() function it doesn't nor for validation...

PHP Code:

public function setLanguage($real_language)
 {
    $language = \Config\Services::language();
    $language->setLocale($real_language); 

    /*just for debuging*/
    $session = \Config\Services::session();
    $session->set('language',$real_language);
    $session->set('locale',$language->getLocale());

return redirect()->back();
}