Replace language-specific characters by ASCII-equivalents.

replace_str_by_ascii.php

<?php
    /**
     * Replace language-specific characters by ASCII-equivalents.
     * @see http://stackoverflow.com/a/16427125/529403
     * @param string $s
     * @return string
     */
    public static function normalizeChars($s)
    {
        $replace = array(
            'Ä' => 'A', 'Å' => 'A', 'Æ' => 'AE', 'È' => 'E', 'Ë' => 'E', 'Ì' => 'I', 'Î' => 'I', 'Ï' => 'I',
            'Ñ' => 'N', 'Ò' => 'O', 'Ö' => 'O', 'Ø' => 'O', 'Ù' => 'U', 'Û' => 'U', 'Ü' => 'U', 'Ý' => 'Y',
            'ä' => 'a', 'ã' => 'a', 'á' => 'a', 'à' => 'a', 'å' => 'a', 'æ' => 'ae', 'è' => 'e', 'ë' => 'e', 'ì' => 'i',
            'í' => 'i', 'î' => 'i', 'ï' => 'i', 'Ã' => 'A', 'Õ' => 'O',
            'ñ' => 'n', 'ò' => 'o', 'ô' => 'o', 'ö' => 'o', 'ø' => 'o', 'ù' => 'ú', 'û' => 'u', 'ü' => 'ý', 'ÿ' => 'y',
            'Œ' => 'OE', 'œ' => 'oe', 'Š' => 'š', 'Ÿ' => 'Y', 'ƒ' => 'f', 'Ğ'=>'G', 'ğ'=>'g', 'Š'=>'S',
            'š'=>'s', 'Ş'=>'S', 'ș'=>'s', 'Ș'=>'S', 'ş'=>'s', 'ț'=>'t', 'Ț'=>'T', 'ÿ'=>'y', 'Ž'=>'Z', 'ž'=>'z'
        );
        return preg_replace('/[^0-9A-Za-zÃÁÀÂÇÉÊÍÕÓÔÚÜãáàâçéêíõóôúü.\-\/ ]/u', '', strtr($s, $replace));
    }