if(filter_var($_POST['username'] , FILTER_VALIDATE_REGEXP,["options"=> [ "regexp" => "/^[\p{L}0-9\s]+$/"]]) === FALSE)
{
$errors[] = ["name" => "username", "error" => "Usernames may not contain symbols"];
}
So basically I have been reading about regexp,I wanted to validate every language however it's failing somehow, so in example it should allow 中文 ect.