Check UTF-8 input in PHP: only letters

This is a simple way to check a UTF-8 string with PHP function preg_match in search for anything that isn't a letter, which includes all UTF-8 letters and not just ASCII. Preg_match performs a regular match on the given input using a pattern. The pattern used tells preg_match to look for letters (\p{L}) using Unicode (/u).

The function to accomplish this could look like this:

<?php

function checkUTF8Input($input) {
	$pattern = '/^[\p{L} ]+$/u';

	preg_match($pattern, $string, $matches);

	if (count($matches) > 0) {
  		return true; // String is OK (only letters)
    } else {
	  return false; // String has non-utf8 letters
    }
}

Take a look at preg_match to know more about this function used for regex operations.