I was looking through the "Skyrim General Discussion" and I can't believe nobody has noticed this yet. If you go to the UESP website they have the "lyriqs" (for lack of a better word) of what the man says in the trailer. One thing that caught my eye was the last phrase.
"In their tongue, he's Dovahkiin: Dragon Born!".
It seems, to me, that we have discovered the first word in the dragon language. Please comment.
Edit: By the way, for those wondering how it's said its (du-vĂ¡-keen).