[Andreas]

PHP Code:

<?php
if (!isset($_GET'lang']))
{
    $lang = 'nl';
}
else
{
    $lang =& $_GET['lang'];
}

if ($lang == 'en')
{
    ?>
    <div align="center">
    <p align="justify">English Text</p>
    </div>
    <?php 
}      
else
{
    ?>
    <div align="center">
    <p align="justify">Dutch Text</p>
    </div>
    <?php
}
?>

This defaults to nl if lang is not set or anything other than en.
Anyway, mixing code and data is no good practice!

I'd suggest to use a template engine.