I'm uncertain if this started with a firefox extension update or not, but it is only affecting the firefox address bar. all other menus, etc are in English. typing in a complete address, say "http://www.bbc.co.uk" will load the page, but in a fraction of a second after pressing 'Enter' the address will change to "PH::". This persists after a restart of FF and after a reboot. clicking in the address bar again will occasionally show a longer address in another language characterset, seemingly an Asian one, though which one I can't say. I only have English UK installed as a language pack on firefox. I've not found anything through google or bing that will help.