To me, it sounds like during the trailer when the pitch of the HW theme raises a tone, it sounds like the chanting sings
"Haaaaaaaaail! To Our Kiiiiiiiing Thoooooooordaaaaaaaaaaaan!" Specifically @ 4:48-4:55
The rest of it before/after is extremely hard to make out, if at all. It may be Dragonspeak still.
Will be interesting what the full theme does sound like. Seems like an incredible fight.
Minstrel's*...