The full sentence I need help translating is:
"Fly in haste to the keep of Barad Falas, where we tarried on our way here, and bear them this message."
Fly as in a messenger bird flying...
Thanks!
I would offer:
Revio lim n’i ost Barad Falas, ias darthannem v’i lend ven na hí, ah anno i vent hen athin. Revio sui aew mint revia. (Fly fast to the fort of Barad Falas, where we stayed/waited in our journey towards here, and give to them this message. Fly as a bird of messages flies.)
However I’m not very certain on the accuracy of this translation; someone more experienced should probably check this over. :)