Codeigniter-无法调用系统的lang（）函数

Fatal error: Call to undefined function lang()

$def_actions[\'add\'] = array(\'name\' => lang(\'carbogrid_add\'), \'alias\' => \'add\', \'url\' => $this->add, \'icon\' => \'ui-icon-circle-plus\', \'toolbar\' => TRUE, \'grid\' => FALSE);

$this->load->helper(\'language\');

$def_actions[\'add\'] = array(\'name\' => lang(\'carbogrid_add\'), \'alias\' => \'add\', \'url\' => $this->add, \'icon\' => \'ui-icon-circle-plus\', \'toolbar\' => TRUE, \'grid\' => FALSE);