"Haven't quite mastered the trick of dragons yet, alas," Jonas laments. "They're much trickier than their mere forms suggest. Besides, we should probably stick to the ground."
Oddly enough, he doesn't turn back into a humanoid form! Rather, the horse speaks perfect common.
"I know some faster shapes, but if you're new to riding, let's stick with the horse for now. You'll have it easier than most beginners, since I'm...you know...sentient."