protected function _sortLanguagesCallback($oLang1, $oLang2)
    {
        $sSortParam = $this->_sDefSortField;
        $sVal1 = is_string($oLang1->$sSortParam) ? strtolower($oLang1->$sSortParam) : $oLang1->$sSortParam;
        $sVal2 = is_string($oLang2->$sSortParam) ? strtolower($oLang2->$sSortParam) : $oLang2->$sSortParam;

        if ($this->_sDefSortOrder == 'asc') {
            return ($sVal1 < $sVal2) ? -1 : 1;
        } else {
            return ($sVal1 > $sVal2) ? -1 : 1;
        }
    }