Multilanguage site utility script

_lang_util.php

<? 
/* _lang_util.php - Multilanguage site utility script
 * This is my basic script to detect language and keep it in a cookie
 *
 * Language priority, from lowest to highest :
 * - default lang
 * - browser accepted lang
 * - cookie lang
 * - query parameter lang
 *
 * To switch lang, add query string lang=[lang_code]
 *
 * Francois Gelians
 * http://fgelinas.com
 * April 2012
 *
 */

global $lang;

$langs = array('en', 'fr'); // site available languages, by priority

$lang = 'en'; // default lang

// detect browser lang, low priority
// here we keep the first lang in $langs that is accepted by the browser, not necessary the preferred browser lang.
if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
    foreach ($langs as $lang_code) {
        if ( strpos( $_SERVER['HTTP_ACCEPT_LANGUAGE'], $lang_code ) > 0) {
            $lang = $lang_code;
            break;
        }
    }
}

// detect cookie lang, medium priority
if ( isset ($_COOKIE['lang']) ) {
    if ( in_array( $_COOKIE['lang'], $langs ) ) {
        $lang = $_COOKIE['lang'];
    }
}

// detect lang in parameter, high priority
if ( isset ($_GET['lang']) ) {
    if ( in_array( $_GET['lang'], $langs ) ) {
        $lang = $_GET['lang'];
    }
}

// save detected/selected lang in cookie
setcookie('lang', $lang);


// quick translate function, get text in current lang
// there is a problem here as this is built for a french/english site, update to your needs
function tr( $french, $english) {
    global $lang;
    if ($lang == 'fr') {
        return $french;
    } else {
        return $english;
    }
}

// basic lang check
function is_french()
{
    global $lang;
    return $lang == 'fr';
}

// basic lang check
function is_english()
{
    return ! is_french();
}