Sorry my friend, but you can't on the S30, and you cannot add your own pois or download any for that matter and add them to your unit....You will req the S50 for that where you can add all your own POI and voices.
I have no voice on my s30. Speaker is working aswell as external speaker. I can hear when I touch screen. I used the CD but that don't load up. Any change you can provide the voice files for my s30 or a complete updater program.