You could easily trigger it, I suppose. I don't think there would be any other way other than to re-import the sounds.
I used Shandris' sounds because I didn't spend the time to find Sylvanas' :p
Anyways, I made some triggers:
Now, there are a few problems with this system. First, the portrait does not look like it's talking. Second, I couldn't get it to work when the unit moves. It plays no sound when you order her to move. Perhaps someone can help with that. Anyways, I really hope this works for you!