I only want to allow users to use letters, numbers and some foreign letters. This works but it removes foreign letters (like öçşğ).
preg_replace('/[^a-zA-Z0-9\s]/', '', $nick)
So I have used below to allow some foreign letters, but it still removes the foreign letters.
preg_replace("@[^A-Za-z0-9\- şıüğçİŞĞÜÇ]+@i","",$nick);
What is the correct approach for allow them ?