For the king for the king
For the fate of Skyrim
For our land for our home for Hrothgar's blood
For the Nord for the gods for the sole single son
Dovahkin, our king, who'll dawn with fire
That's the general consensus of what the chorus chanting is actually saying. It does make sense because Hrothgar is Nord term and Nords = Skyrim.
In the end of the teaser you see the Akavir symbol. If you know much about the Elder Scrolls lore, the Akavir invaded Tamriel before and was defeated at the Pale Pass, which is at the Cyrodil-Skyrim border. You can visit the area in Oblivion and there are Akaviri ghosts in the fort from the remnants of the battle. Where did the Akavir invade Tamriel from? Skyrim! Also Akavir is the supposed home to dragons. It says the sons of Skyrim spilled their own blood, obviously means that there's a conflict within Skyrim and the Akavir are seeking to re-invade Tamriel through Skyrim.
One point I don't get is that the dragonborn is half dragon. Does that mean he is part Akaviri? Dragonborns are all emperors, if you remember from Oblivion, "All hail Martin dragonborn!" or something like that.
At least that's my interpretation of the plot from the trailer.
This is the Akaviri symbol:
Edited by Oh Snapalope - 1/10/11 at 2:10am