If you want to translate the language variable, then you can go to FTP of your WHMCS and go to this location WHMCS/modules/servers/vmware/lang and make a copy of English.php to dutch.php and edit this dutch.php file and translate the whole content in your language
Note. For other languages you have to do same thing. For example you want to add Farsi, then do same thing make a duplicate copy of english.php and rename it to farsi.php and then translate the text.
