Messing around with the forcegreet dialogue from the DialogueCrimeGuards quest, and having a hard time. Duplicating a topic makes the second version not have any voice sound. Converting it into a shared info also seems to prevent the voice files from working. I'm at a complete loss on how to do this.

Voice files are mapped to the specific ID of a topic. If you Look under Sounds/Voice/Skyrim.esm you'll see all the Skyrim voice files, sorted by voicetype, and named by topic info audio ID.

If you convert something to a shared info, it changes it's ID, and the respective audio file will have to be renamed to match as well as be moved into the plugins voice folder. (Sounds/Voice/YourPlugin.esp/Voicetype/TopicInfoID)

For extra info, see this tutorial, more importantly the "Voice Filename" part in the pictures near the bottom under "Recording a temp track": http://www.creationkit.com/Bethesda_Tutorial_Dialogue