My function add preg_replace to remove some character non-english like in "Bài, Bá, Bách"
function stripUnicode($str){
if(!$str) return false;
$unicode = array(
'a'=>'á|à|ả|ã|ạ|ă|ắ|ặ|ằ|ẳ|ẵ|â|ấ|ầ|ẩ|ẫ|ậ',
'D'=>'Đ',
'd'=>'đ',
'e'=>'é|è|ẻ|ẽ|ẹ|ê|ế|ề|ể|ễ|ệ',