I just ran iCleanLanguage and gained 3 GB. That is good as my MacBook only has a 160 GB hard drive. It removes the 100 (?) excess languages that automatically come with the system and many applications. I removed everything but Spanish. English automatically stays as the default language. Because of conflicts it does not remove languages from Adobe products and MS Office, but 3 GB is a sizeable gain in hard drive space. The program is free, a donation is optional.
Contributed by Marvin Robertson on Mac-Min, October 2010