The primary Language spoken throughout the world is the Ethsharitic Language - the language of the Hegemony of the Three Ethshars and the least-drifted version of the language of Old Ethshar. Throughout the Small Kingdoms a couple of hundred languages are spoken, though all are fairly close relatives of Ethsharitic, making it easier to pick up new Small Kingdom tongues as more of the languages are learned. There is also the Trader's Tongue, a pidgin of some of the more common Kingdom tongues developed by merchants to facilitate trade and commerce.
Originally mankind had one language, which then fragmented for unknown reasons. There were at one point as many as 15 non-Ethsharitic language families, but all are believed to have have died out. Many of the last remaining languages were lost as their speakers were absorbed into the Northern Empire, and the last as a result of the utter destruction of the Empire at the conclusion of the Great War. The last non-Ethsharitic language was the administrative and military language of the Northern Empire, Shaslan. In the Northern Lands there are a variety of languages which incorporate aspects of this language, including Sardironese