PHP Beginners: How to Add Multi-language Support to a Website

Posted on July 23, 2009, Filled under PHP, Bookmark it

Are you interested in having a multilingual website? This is a tutorial that shows you how you can do that in PHP.

php-multi-language-site

The first thing we need to do is to create a couple of files that will contain the text for each of the languages that will be supported by the website. For demo purpose I have chosen English, Spanish and German. Make a directory named “directory”. In this directory create 3 files: lang.de.php, lang.en.php, and lang.es.php. In our main file (index.php) we will include a file (common.php) containing a piece of code that gets the requested language. Here’s the content of those 3 language files:

lang.en.php

<?php
/*
------------------
Language: English
------------------
*/

define('LANG_PAGE_TITLE', 'My website page title');
define('LANG_HEADER_TITLE', 'My website header title');
define('LANG_SITE_NAME', 'My Website');
define('LANG_SLOGAN', 'My slogan here');
define('LANG_HEADING', 'Heading');

// Menu

define('LANG_MENU_HOME', 'Home');
define('LANG_MENU_ABOUT_US', 'About Us');
define('LANG_MENU_OUR_PRODUCTS', 'Our products');
define('LANG_MENU_CONTACT_US', 'Contact Us');
define('LANG_MENU_ADVERTISE', 'Advertise');
define('LANG_MENU_SITE_MAP', 'Site Map');
?>

lang.es.php

<?php
/*
------------------
Language: Spanish
------------------
*/

define('LANG_PAGE_TITLE', 'TÃtulo de la pÃ¡gina de mi sitio web');
define('LANG_HEADER_TITLE', 'Mi sitio web de la cabecera tÃtulo');
define('LANG_SITENAME', 'Mi Sitio Web');
define('LANG_SLOGAN', '	Mi lema aquÃ');
define('LANG_HEADING', 'TÃtulo');

// Menu

define('LANG_MENU_HOME', 'Inicio');
define('LANG_MENU_ABOUT_US', 'Sobre Nosotros');
define('LANG_MENU_OUR_PRODUCTS', 'Nuestros productos');
define('LANG_MENU_CONTACT_US', 'ContÃ¡ctenos');
define('LANG_MENU_ADVERTISE', 'Publicidad');
define('LANG_MENU_SITE_MAP', 'Mapa del Sitio');
?>

lang.de.php

<?php
/*
-----------------
Language: German
-----------------
*/

define('LANG_PAGE_TITLE', 'Meine Webseite Titel');
define('LANG_HEADER_TITLE', 'Meine Website-Header Titel');
define('LANG_SITE_NAME', 'Meine Website');
define('LANG_SLOGAN', 'Mein Slogan hier');
define('LANG_HEADING', 'Position');

// Menu

define('LANG_MENU_HOME', 'Heim');
define('LANG_MENU_ABOUT_US', 'Ãœber uns');
define('LANG_MENU_OUR_PRODUCTS', 'Unsere Produkte');
define('LANG_MENU_CONTACT_US', 'Kontaktieren Sie uns');
define('LANG_MENU_ADVERTISE', 'Werben');
define('LANG_MENU_SITE_MAP', 'Site Karte');
?>

As you can notice, some constants are created using the define() function. In every file the defined constants have the same name, bu the values is different. We will output the values of the constants inside the index.php file. Therefore we will see different text every time we will call other language file.

Determine the right language

Let’s analyze the common.php file:

<?php
session_start();
header('Cache-control: private'); // IE 6 FIX

if(isSet($_GET['lang']))
{
$lang = $_GET['lang'];

// register the session and set the cookie
$_SESSION['lang'] = $lang;

setcookie('lang', $lang, time() + (3600 * 24 * 30));
}
else if(isSet($_SESSION['lang']))
{
$lang = $_SESSION['lang'];
}
else if(isSet($_COOKIE['lang']))
{
$lang = $_COOKIE['lang'];
}
else
{
$lang = 'en';
}

switch ($lang) {
  case 'en':
  $lang_file = 'lang.en.php';
  break;

  case 'de':
  $lang_file = 'lang.de.php';
  break;

  case 'es':
  $lang_file = 'lang.es.php';
  break;

  default:
  $lang_file = 'lang.en.php';

}

include_once 'languages/'.$lang_file;
?>

After we determine the value of $lang, we use switch() to compare its value with some different values, and execute a different piece of code depending on which value it equals to. After the value of the $lang_file is determined, the script will include the necessary language file. As you can see I have used sessions to register the value of $lang. This way users can navigate through the whole site and see the content in the chosen language (lang=[language here] does not need to be passed in every URL). Additionally, I have used cookies to store the selected language in users computer for 30 days. When the visitor will come back he will see the site in the language that he previously selected.

How if the website’s language requested?

In this demo I have chosen to use some image flags, each image having a link to index.php?lang=[LANG HERE]. So, to see the site in german we will use the German image flag which links to index.php?lang=de.

Lastly, the constants values should be outputted in the page. Examples:

for document title

<title><?php echo LANG_PAGE_TITLE; ?></title>

for header menu

 <ul>
      <li><a href="/"><?php echo LANG_MENU_HOME; ?></a></li>
      <li><a href="about_us"><?php echo LANG_MENU_ABOUT_US; ?></a></li>
	  <li><a href="our_products"><?php echo LANG_MENU_OUR_PRODUCTS; ?></a></li>
      <li><a href="contact_us"><?php echo LANG_MENU_CONTACT_US; ?></a></li>
      <li><a href="advertise"><?php echo LANG_MENU_ADVERTISE; ?></a></li>
      <li><a href="sitemap"><?php echo LANG_MENU_SITE_MAP; ?></a></li>
    </ul>