Need Help

Hello There i have written a code like this ----------------------------------------------------------------------------------------------------- $text="سلام من حامد هستم"; function slugify($text) {   // replace all non letters or digits with -   $text = preg_replace('/\W+/', '-', $text);   // trim and lowercase   $text = utf8_to_unicode( strtolower(trim($text, '-')));   return $text; }  echo slugify($text); but when I try it in English it works $text="Hi iam hamed"; function slugify($text) {   // replace all non letters or digits with -   $text = preg_replace('/\W+/', '-', $text);   // trim and lowercase   $text = utf8_to_unicode( strtolower(trim($text, '-')));   return $text; }  echo slugify($text); please help me Thanks