If you're noticing that the high quality voice seems to download repeatedly or attempts to start downloading after a device reboot, please try the following:
1. Go to Settings > Applications > Manage applications (may also be labeled Application Manager).
2. Tab over to All.
3. Select the Dragon Mobile Assistant app, and then tap Force Stop and Clear Data.
4. Go back to All.
5. Select Download Manager (may also be labeled Downloads) and tap Clear Data.
6. Relaunch Dragon Mobile Assistant.
Note that clearing an app's data will likely cause it to lose all of its settings, so you may need to reconfigure Dragon Mobile Assistant after following this procedure.