# The Friendly URLs part
# detect language when requesting the root (/)
RewriteCond %{HTTP:Accept-Language} !^(nl|fr) [NC]
RewriteRule ^$ nl/ [R=301,L]
RewriteRule ^$ fr/ [R=301,L]

<?php
$lang = strtok($_SERVER['HTTP_ACCEPT_LANGUAGE'],",");
    while ($lang)
    {
         //check if the language is dutch
         if (strstr($lang,"nl"))
         {
              header ("location: ".$modx->makeUrl(25, '', '', 'full'));
              exit;
          }
          //check if the language is french
          if (strstr($lang,"fr"))
          {
              header ("location: ".$modx->makeUrl(24, '', '', 'full'));
              exit;
          }
        // etc..
                  
         $lang = strtok(",");
     }
      
     // no defined language found, go to the french pages
    header ("location: ".$modx->makeUrl(24, '', '', 'full'));
    exit;
?php>