In 12.04 I cannot use in Unity its default Keyboard layout switching mechanism. It doesn't matter how many and which layouts are added, only keyboard defined in xorgs (or possibly configurable manually using sudo setxkbmap -option grp:alt_shift_toggle "us,cz") appears in system. So what to check why it doesn't work or how to bind setxkbmap directly?
To configure keyboard layout manually
Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.