The Lord of the Rings: Shadow of the East
Westron is spoken or known by most Men in the West. Dwarves use Westron (see Dwarvish Westron) or, to a much lesser degree, Sindarin while “in public”. Where a number of different races meet in council or to discuss affairs, Westron is employed as a common ground.
Westron is actually a mixture of debased Adûnaic and various Endorian dialects. While it incorporates numerous Sindarin, Northman, and Southron influences, Adûnaic provides most of the vocabulary.