Well, generally, I think the process is something like... first they do all of the initial work (translating, etc.) and get it all programmed for an English release which, I should add, probably involves a fair amount of help from the developers. You know, the people making the game busy making new content for the original version, plus any other overseas versions, plus any other games they have. Lots of this initial work can take time. Then you've probably got an alpha test (there's a reason what they give us is the "beta", after all) in-house and/or in conjunction with the developers to gather info on how it's working, after which they'll probably have to do more programming (again, doing so alongside everything else being programmed) and possibly another round of testing (or two or three, depending on how it goes) before they're ready for the beta. Which they then have to actually set up, including programming the servers with the game and any final checks before it's open.
So, yeah, this can take time. XD I doubt it's just Aeria working, and sometimes they may have to effectively twiddle their thumbs. That said, I'm reasonably confident that the CBT will begin within the first half of this year; they announced the game a couple of months ago, after all, and a game that isn't running isn't making them any money, so both they and the developer have the incentive to get it going.
In the meantime, though, I'm really glad that they're giving us the Lore Expansion project. ^^ I rather enjoy such things, and it's a lot better than hearing nothing at all about the game world for months on end.