Sure! This is mostly used for detection and then translation of a webpage.

Function getPreferredLanguage() {
    $langs = array();
    if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
        // break up string into pieces (languages and q factors)
        preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})?)s*(;s*qs*=s*(1
0.[0-9]+))?/i',
                $_SERVER['HTTP_ACCEPT_LANGUAGE'], $lang_parse);
        if (count($lang_parse[1])) {
            // create a list like "en" => 0.8
            $langs = array_combine($lang_parse[1], $lang_parse[4]);
            // set default to 1 for any without q factor
            foreach ($langs as $lang => $val) {
                if ($val === '') $langs[$lang] = 1;
            }
            // sort list based on value    
            arsort($langs, SORT_NUMERIC);
        }
    }
    //extract most important (first)
    foreach ($langs as $lang => $val) { break; }
    //if complex language simplify it
    if (stristr($lang,"-")) {$tmp = explode("-",$lang); $lang = $tmp[0]; }
    return $lang;
}

By www.barattalo.it