I downloaded a couple of US computer voices into my Sandisk 4GB SDHC card and all seemed ok. TT Home showed it as being installed. The card is formatted FAT32 like i've read here and windows explorer sees it as another removable device. I disconnect my TT920 from my pc and when I select the voice I just downloaded, no sound at all. So I remove it from the sd card via TT Home, download it to internal memory and then it works. So why doesn't it work when I have it installed on my sd card?