I'm using a clean install of Freya (made about a month ago), and suddenly Software Updater started including all these language packs.
I had the same issue with a previous install of Freya; it just looks like, after a while, elementary just decides to start installing all these language packs.
By the way, the only language I have installed is english (the default one) and I'm using an Italian keyboard, as you can see above.
EDIT - after using sudo apt-get remove firefox-locale-*
it seems for now that elementary has stopped trying to install those packages. Of course, this removes every language pack in Firefox, which I however didn't have to begin with.