I would do this then (assuming I know what you're after):
Create a words array:
$translate = array();
Now, for every word (you could translate full sentences or phrases too), we'll create an element:
$translate['Naam'] = array('Vorname', 'First Name', 'Nombre');
Now simply insert code before your Vorname box:
<?=$translate['Naam'][$_GET['langue']]?>
Depending on which $_GET['langue'], you'll get a different language.