Njetoluhi is a "water world." Civilization is limited, and is distributed on small islands and filled pools.
A filled pool is essentially a whirlpool that is so powerful that it has filled itself with flotsam. Curiously, although these are typically about 15 meters below the surface, they are stable and livable. The water simply flows around the outside. Unfortunately, they are almost completely cut off from the outside world, since any ship approaching will probably be destroyed. (Approaching fish can be netted.) There are two ways to enter a filled pool. One, usually used by humans, is to take a large wooden ring with a deck and platform. Once this is towed (by a large fleet of ships, although some have very large sails instead) into place, you can simply throw down a rope--although this makes people dizzy. The Elves can also use magic to freeze the whirlpool.
Filled pools are relatively common, and about 20 people can live comfortably in one. Although it can serve as a trading base, it is typically safer to store items above.
Cenoji is the main language of the Sea Elves. These Elves do not live underwater, although they can go under for long periods (about half a day). The Elves typically live in clans aboard the aforementioned wooden rings. Their society is de facto decentralized and peaceful, but in law the High King of All Elves maintains rule.
Cenoji is a simple language yet heavily agglutinating. See the link above for more information.
Most of the Elves are traders. Some live in filled pools, others live on small islands, some stay permanently on their boats, and the rest live on the "mainland." This is really a fringe of livable beach, with an impenetrable forest past it.