public function change($id = null)
    {
        if ($id === null || !$this->Languages->exists(['id' => $id])) {
            $this->Flash->error($this->invalidRequestMessage);
            $this->redirect($this->referer());
            return;
        }
        $this->request->session()->write('contentLanguageId', (int)$id);
        $this->redirect($this->referer());
    }