It is stated that Finrod Felagund was able to quickly master Taliska purely by determining the various changes undergone by its Avarin component from Primitive Quendian, and Faramir stated that all languages of Men are of Elvish descent, suggesting that Taliska and Adûnaic are in fact Quendian/Avarin with some Khuzdul influence (notwithstanding the possibility that Faramir was misinformed, much as how many people mistakenly think English is a Romance language).
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Following the Akallabêth, the surviving Elendili who established the kingdoms of Arnor and Gondor shunned Adûnaic in favour of Sindarin due to the associations of the former with the tyrannical Ar-Pharazôn and his followers the King's Men.
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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).