I think Mysteltain has most of it right and that it's definitely a Garlean anthem (it's clearly saying "For Glory, Garlemald!" there at the end). I think I can clear it up a little further:

Beyond majestic mountains
Across the (endless vale?) (this part is the least clear by far, I keep hearing "across the enlo wey-ho" :v )
Oh mighty, mighty standard
United we remain

Fly high beyond the ramparts!
Fly high within our soul!
My every conquest be for thee,

For glory,
Garlemald!