PHP clean url slug generator / converter (slug)

toAscii.php

<?php
// source: http://cubiq.org/the-perfect-php-clean-url-generator
// author: Matteo Spinelli
// MIT License / http://creativecommons.org/licenses/by-sa/3.0/ (please re-check at source)

setlocale(LC_ALL, 'en_US.UTF8');
function toAscii($str, $replace=array(), $delimiter='-') {
	if( !empty($replace) ) {
		$str = str_replace((array)$replace, ' ', $str);
	}

	$clean = iconv('UTF-8', 'ASCII//TRANSLIT', $str);
	$clean = preg_replace("/[^a-zA-Z0-9\/_|+ -]/", '', $clean);
	$clean = strtolower(trim($clean, '-'));
	$clean = preg_replace("/[\/_|+ -]+/", $delimiter, $clean);

	return $clean;
}

// usage:
echo toAscii("Peux-tu m'aider s'il te plaît?", "'"); // French
// returns: peux-tu-m-aider-s-il-te-plait

why single quote coming as 39?