Hi Julie:
The two links that Gypsy provided will lead you to exactly what you are looking for, however, there is a much easier way to get the voices, and this method works for
ANY GPSR - plus, it even installs the voices for you.
Go to the Garmin website and download the latest version of the
WebUpdater program, then install this program on your computer. Now, power up your GPSR and connect it to your computer using the same cable you use to transfer waypoints, maps, tracks, etc. Launch the WebUpdater program from your computer - the same way you launch any other program on your computer - and then follow the instructions.
WebUpdater will complete two update cycles on your GPSR if you have a GPSR that supports voice guidance. The first update cycle will update the system software within your GPSR. Once that is done, watch for a little message that will say "There might be further updates for your GPSR, do you want to check?" This indicates that new updates for the voices have become available (if you have the latest voices on your GPSR, you won't get this message). If you answer 'yes' to that question, you will then be presented with a list of voices - with different regionalizations and different languages - that you can choose to download. You can download as few or as many as you want.
Be aware that the voices that have proper names associated with them (e.g. American English - Jill or German - Yannick) are only used by GPSRs that support the text to speech feature - the ones that say "In 300 feet, turn left on Nottingham Road", rather than just "In 300 feet, turn left". So, there is no point to downloading the 'named' voices unless you have one of the newer model GPSRs that supports TTS.
Michael