Here’s a useful little utility for OS X:
It allows you to remove languages, input methods and architectures that you don’t require (think: all of the translated help files that you will never use).
It took about 10 minutes to free up about 1.2 GB on my system. Your results may vary.
PS look closely at the list of languages in the screen shot above and see if any of them are familiar. Klingon, anybody? :-)