Isn't that just a desert biome leaking over...?
Nope, it's beach. Says so on the wiki, and there's no desert nearby. The problem is the new hilly code seems to be negatively effecting beach since it is nothing more than a water's edge layer.
Turns out they added Pirate Speak to the Language Selection in 12w01a! GameChap was showing it off, didn't realize until now. If they add such Languages, what is to keep them from adding Dragon Language? :P Copyrights.
Oh, and for all you complaining about the abrupt transition between Swamps and other biomes, there is finally a gradient for it.