Gildspeak

Gildspeak (or Common) is the most common language throughout the Merchant Sea region, spoken in most open societies. It is especially widespread in Sheanora, used among the peoples' of Aracia, Arcenveld, Mephistia, Tionmenel, Torcest and Glimmerhome. 
Gildspeak was created by dwarven traders and merchants in Torcest, a few centuries after the Great Migration that brought Humans and Elves from the south in Vul'Badir. It was designed as a means to easily communicate between the - at the time - Dwarven and Orcish natives of Sheanora and the expanding settlements of Humans and Elves. As such, it features elements common amongst all of these varying languages, but has a base of dwarven. The few dwarves that don't speak Gildspeak can still understand much of its syntax. 
Its usefulness as a trade language that is fairly easy to learn has led to its rapid expansion even beyond the Merchant Sea region.