Not conclusive, but I have noticed that disabling those extra language installations doesn't really work. I have a system bought in Japan and even with only Japanese and English selected for installation, I still get Arabic and Chinese fonts installed that can not be removed via Font Book, they are used as system fonts. I have Englsh selected as the top of 2 languages in the International system preferences pane, all other languages edited out of the list. But there are still foreign language support files installed. YMMV depending on the origin of the system, are you in the States or the UK?
In any case it can't hurt to try to disable the install of languages you will definitely not use, but it won't really save all that much space either. It's kind of a non-issue IMO.
