Holy 13th Warrior!
I actually understood some of that and I do not speak Norwegian!
The trick is to watch the flash, then close your eyes as you watch it again. Just relax and let the words just be themselves. Many are close enough to english that you can make out enough to follow the gist of it.
But yeah, subtitles are still required. But seriously, watch it with your eyes closed and just let the words hit your eardrums without thinking about them. It will amaze you how many you will actually recognize.