In Ubuntu, if you want to view your current keyboard layout, you need to go into Keyboard Preferences and open up a rather bulky keyboard to refer to. None of the accessibility-oriented on-screen keyboards that I found through apt or the repository support alternate input layouts or alternate input languages by default. Please consider finding some on-screen keyboard that displays the current input layout to include in Ubuntu's default config. This is a basic international functionality need which could easily be met in Ubuntu's default install package.
xvkbd used to run fine until Ubuntu 5.xx (try 'sudo apt-get install xvkbd'), but it seems to some kind of library replacement or updating stopped xvkbd working fine on Gnome applications...
As well, the sources of xvkbd are there, maybe someone can do a gnome-based port would work fine on applications runs fine on Gnome...
Update: I realize that the layout switcher, when you right-click on it, has an option for "Show current layout". Still, this functionality should have more visibility; as far as I know, right-clicking the layout switcher is the only way to find that window.
I tried to type in Tamil. I installed the required font and keyboards and I have the option of switching between English and Tamil. No issues. I want to use Tamil in Office I do not know which button to press for which character in Tamil. Ubuntu / Office can have an option to display the onscreen key board, so that it easy to learn typing other than english. I use Ubuntu 10.04. Kindly ignore this advice if it is implemented in Ubuntu 12.04