localization includes a lot more than just translating/patching a game!
this is the normal process
•Step 1: Familiarization (1-3 weeks) -- Play the game and understand context of written material.
•Step 2: Localization (1-8 weeks) -- Depends on amount of text and if voice acting is required.
•Step 3: Programming (4-6 weeks) -- All implemented by original developers.
•Step 4: Quality Assurance (5-8 weeks) -- Bugs are natural side effect of localization, along with "test issues."
•Step 5: Manufacturer Approval (3-8 weeks) -- "Internal testers go over the submitted master candidate."
•Step 6: Manufacturing (3-5 weeks) -- Print, box and ship
and beyond that, they have to run it through and check everything in the game against NOA and esrb standards and stuff. and it has to go through multiple departments for review, because once they release a game, they can't exactly just release a patch if they have any bugs in it. like the walk through walls bug in diamond and pearl, they also let it sit for a while to see if the initial release community can find any bugs that escaped people intially bug testing it. also, localization usually has things being changed to more american sounding things as well. and this has taken a tiny bit of time, but the surface has barely been scratched, as far as storyline goes.