Adûnaic derived from the closely related Bëorian and Hadorian dialects of Taliska, the language spoken by the first and third houses of the Edain when they first entered Beleriand during the First Age (the language(s) of the second house, the Haladin, seems to have had little or no influence on Adûnaic whatsoever, despite the apparent presence of both the Haladin and the Drúedain in Númenor prior to its downfall).
These centred around a series of wars waged by the Sindar, the Noldor and the Three Houses of the Edain against the armies of Angband and the evil Men from the East.
A similar principle was used by the High Kings of the Noldorin Elves, with whom the Edain of Númenor had had extensive dealings.