It's no trick. There's hardly anyone else around who could be seeming to speak for her, and she certainly seems to be alone. Of course, with the fog it can been hard to tell one way or the other but it does seem to be that she's actually speaking.

"Oh. They might be very different sorts of dragons, then."

Which is interesting in a mild sort of way, but any dragons she doesn't recognize are only a minor interest if they aren't actually around for her to see.