Aquan

Aquan is the language of the Marid spoken primarily in the Realm of Order and the oceans of Aesalia. 
During the War of the Realms the Marid sought to make alliances with creatures beneath the waves, most notably the Kraken, and in doing so taught many of the creatures how to speak aquan with the aid of magical items and tricks. As a result the various mer that dwell beneath the waters have learned aquan as their own language speaking it freely with only small pronunciational differences to the original Marid dialect.