User blog comment:Megadracosaurus/Dragon Episode/@comment-4122072-20140724092131

Personally, I believe that dragons communicate through telepathy (they can read each other's minds), so you'd hear them talk, but their lips don't move. This episode would temporarily tap into that power.

In the books, the Seadragonus Giganticus Maximus could use telepathy, so why can't the dragons in the franchise use it?