Sound files like that are kept in .utf files (so can of course be opened by UTFEdit). This sadly is where the easy bit ends...
All the internal sound names are stored in CRC encoded format, so you'll have to find the right number to go with the sound then find the .utf that contains that number.
Next (oh yes it goes on) you have to find the rest of the component parts of the 2 or 3 that will be used to make the whole broadcast! Are we having fun yet modders? If the announcer references a ship, it will want the sound file associated with that faction (which is why when custom factions are used you get blank parts in the broadcasts). When referencing the player, you will also need to match up a voice to the 1-1 (or X-N in MP game).
So.... making new sounds for factions and even just modifying current ones is sadly one huge headache. Sorry I can't give you better news on it
+++ out of cheese error - redo from start +++