Chances are you only use one language on your Mac. For me, that’s English, so having an exhaustive list of additional languages installed on my machine is unnecessary.
Fortunately, a little utility called Monolingual allows you to uninstall any and all languages you don’t need. The process couldn’t be simpler: once you fire up the app, just select the languages you don’t want, and click Remove. It actually takes longer than you’d think, but once the process completes, you’ll have regained many megabytes of disk space. I just used it on an old iBook G4 and reclaimed an impressive 1.5GB.
The other way to do this is to customize your initial OS X install and leave out the extra languages, but for those of us who forgot or don’t know how to do that, Monolingual is very handy.