I love the sound of Japanese. It is a syllable timed language which means all the syllables are pronounced with the same timing. Italian is another syllable timed language. English, on the other hand, is a stress timed language which means stress syllables come at regularly spaced intervals.
As for the trailer though, hearing Japanese in a medieval setting makes me think of Samurai. “You have brought dishonour on this house, Baratheon! Do not send those assassins, it would be very dishonourable!” someone would say at the small council meeting. “A samurai always pays his debts” 😀