I hope this is the correct forum for this, but I was writing up a new character from Altumbel today and saw one of the bonus languages is "Serusan". I've never heard of this language before, and couldn't find any info on it in a quick search of my books.
Does anyone have any info on this language, or know where it comes from? It's used in Altumbel and the Wizard's Reach, but that's I could come up with.
To expand on Krash's answer a bit... The nations and city-states living within (as in, underwater) the Sea of Fallen Stars call the region "Serôs." So the common language of this area is Serusan.
I'd say it's not a useful language unless you spend a lot of time talking to folks underwater.