Varför accepterades Westron-tungan som den gemensamma tungan i Middle Earth?

Westron utvecklades från det numenoranska språket Adûnaic, som i sin tur utvecklades från Atanis antika språk i första åldern. "Adûnaic" är klart, Adûnaic för "Westron" (!!!)

Det tydligaste uttalandet av detta ges i Ringenes Herre Bilaga F:

In the years of their power the Númenoreans had maintained many forts and havens upon the western coasts of Middle-earth for the help of their ships; and one of the chief of these was at Pelargir near the Mouths of Anduin. There Adûnaic was spoken, and mingled with many words of the languages of lesser men it became a Common Speech that spread thence along the coasts among all that had dealings with Westernesse.

After the Downfall of Númenor ..... They used therefore the Common Speech in their dealing with other folk and in the government of their wide realms; but they enlarged the language and enriched it with many words drawn from Elven-tongues.

In the days of the Númenorean kings this ennobled Westron speech spread far and wide, even among their enemies; and it became used more and more by the Dúnedain themselves, so that at the time of the War of the Ring the Elven-tongue was known to only a small part of the peoples of Gondor...

När det gäller det tidigare uppkomsten ger Appendix F igen beviset:

It was in origin the language of those whom the Eldar called the Atani or Edain, 'Fathers of Men', being especially the people of the Three Houses of the Elf-friends who came west into Beleriand in the First Age...

Således blev språket som blev Westron ursprungligen talat av männen i Beors hus, Hador och Haleth, tagit till Númenor, där det blev Adunéiskt, och så småningom återfört till Mellanöstern under tiden av den numenoranska makten där Det utvecklades vidare till Westron på tiden för ringenes herre.