I had a Langster, and truth be told, I have no idea how much it weighed. At the time, I just never cared much about being a weight weenie. Shortly there after, I purchased a Cannondale Capo, and got that to 14 pounds-ish. I was constantly changing parts, bars, adding and removing my brakes, etc, so sometimes it weighed in a bit more, but other times, less!
First the frame, this was not built specifically as a weight weenie frame choice, while aluminum, it's not the lightest frame around, as it needs to survive the use and abuse specialized designed it for. That being mostly city rides, and commuting, with the occasional banging it around for locking it up, and falling, etc.
As for the fork. it most likely Specialized's heaviest carbon fork, there is no fancy fork going in the Langster to hit the price point it is selling at. I'd imagine a good 1/3 of a pound to even 1/2 just by putting a decent full carbon fork.
Lastly, a few small notes on your build-
You have one of, if not the heaviest tire for that bike. While a bombproof, and ideal city, they are by no means light.
Also, you still have platform pedals equipped with cages.
Certainly plenty of weight can be dropped there with a clipless system.
And you have a computer! Whie not not too heavy, there is yet another source of weight, you won't generally find on those 13 pound bikes.
With all that said, you could certainly drop some weight, however it might make the bike a bit less practical for your needs. It seems you have a solid ride there, and I'd be pretty happy to ride that around town just as it sits now!