the time the port takes depends on a lot factors, if they have to change graphics, videos or such things for the port then it might take a while. But if these things can stay same on both platforms and only the game engine needs to ported and optimized then it won't take too long.
Also Internationalization is done by a specialized team and usually has near to now work included for the engine programmers, so their programmers will be free to work on the 360 engine at that time.







