On the request of a friend, here is how one can change the default language in Ubuntu Gutsy (7.10).
It is actually a pretty simple action, but no one seems to remember how it’s actually being done ! So just go in the System/Administration/Language Support. A window will open, and you can here select the languages that you want your OS to support, and which one you want to make the default one.
The actual pretty slick thing about this, is that all the applications (actually the one supported, but that’s most of them) will reflect this change. So if you made the mistake of installing Ubuntu in French and you’re wife is not happy with it … You have a two clicks exit 😉