if($client_language == "german"){// Do german version of site.} else {// Do english}
<?php echo "Hello World"; ?>
<html><head><title>Hello World</title></head><body><p>Hello World</p></body></html>
$language = getLanguage(); //I won't define this function as it is trivial... its just a way of getting a user's preferred language echo $langauge['header']; echo $langauge['content']; // etc