Okay, so this has been bugging me for a while, and I just need to get a yes or no answer because this is quite useful if it is permitted.

I've been wondering if it is allowed/legal to re-use vanilla dialogue for use in mods for Oblivion. Like, say if I wanted to bring the Emperor back in some way, maybe as a ghost, and I wanted him to have the same dialogue he used before. The ideal solution would be to copy his audio files from the .bsa and then adapt them for use in my mod, renaming them as required by my Dialogue IDs.

Otherwise, I would have to modify every single line of original dialogue in the editor to recognize the new NPC, possibly causing compatibility issues if any other mods edit the same dialogue.

In this mod compilation, http://planetelderscrolls.gamespy.com/View.php?view=oblivionmods.detail&id=2000, there is a Main Quest Delayer and this useful technique is used to give dialogue to the Emperor, whom you can meet in the Elder Council chambers. Judging from this, I would assume it is legal, otherwise he would have been sued by now, but I'm not sure.

So, long story short: Are you allowed to re-use vanilla dialogue for new mods?