John,
While there's probably a language option in the Advanced driver settings(make sure it is set to PostScript, and that you're using a PostScript driver), what you need to verify is the settings on the RIP itself, not in the driver settings. Check the RIP itself, and see if there is an option for language, and make sure it is PostScript. Do the same thing for your printer.
Unfortunately, I do not have access to a Fiery, so I cannot tell you where to look for. You might want to consult your RIP's manual, or contact the RIP's manufacturer if you cannot find it.
Regards,
Rapha