Adûnaic

Though the name Adûnaic cannot have been used before the Edain travelled to Númenor at the beginning of the Second Age, the language itself, or something very close to it, seems to have been spoken in Beleriand during the First Age, at least by the people of the House of Hador. While there is no mention of its use after the Downfall, it cannot have become completely extinct at this date; it seems likely that the scholars of Gondor and of Arnor would have been familiar with the ancient tongue of their ancestors, but in general use Adûnaic was replaced by the Westron (which had developed from it) and Elvish languages.

Following the conventions of Elvish pronunciation, the word would be pronounced a'doon-ike. Adûnaic is not an Elvish word, though, and is in fact so clearly modelled on real linguistic terms such as Hebraic or Aramaic that a pronunciation based on these, a'doon-ayik, seems somewhat more plausible.