Best would be to install the en-US or en-GB Firefox version and install the French language pack in the profile of your daughter and only update Firefox in your account on future occasions. You will have to reinstall languages packs after each update.

You can find the latest Firefox release here:

• Firefox 9.0.x: http://www.mozilla.org/en-US/firefox/all.html

See:

• http://kb.mozillazine.org/Language_packs

Firefox Mac language packs:

• http://releases.mozilla.org/pub/mozilla.org/firefox/releases/latest/mac/xpi/

• Locale Switcher: https://addons.mozilla.org/firefox/addon/locale-switcher/

Yup, that solved it, thanks. At first it wouldn't let me install it on my own account, though, because the stupid Mac had decided that I had made my daughter the owner and that we didn't have enough permissions anymore, but that's happened so many times now that I knew how to fix that. You know, I didn't realize I was updating Firefox for everyone at the time; I thought it would just affect her account. Anyway, thank you.

Since the thread owner has marked the issue as "solved" I'm locking this thread. If anyone has other questions please start a new thread.