Common

Also known as Trade Common, the common tongue of Rhyduania was originally a constructed language. It was intentionally created as a simplified form of Elvish by administrators of the Adlon Empire to facilitate trade, communication and diplomacy between all of its Rhyduanian vassals.
In the 3000 years since the Sundering and the fall of the Adlon Empire, the language has evolved into a wildly different form, having incorporated grammar and vocabulary from the various regional and racial languages of the non-elven populations. There are many regional dialects, but all are mutually intelligible to some degree.