Languages aren't appearing on Settings page


I’ve downloaded the language pack and uploaded the language folder to /wp-content but the language option is not appearing on my admin settings page (single wordpress installation). I really want to use a WPMU solution rather than going back to my old, more confusing solution! Any ideas? (Incidentally, I tried posting this under plugins, but since it’s not actually a plugin it wouldn’t let me, so I figured this was the best place..!)