I'm using PCLinuxOS 2010, which iirc is running KDE 4.5.4.

Is there a way to set it up so that when you switch to another desktop the language used on the system changes?

For example, I am English, but I am learning Russian. I have a desktop configured with various links, applications and widgets for when I sit down to do this, but it would be of great help to me if I could completely immerse myself in the language and have the language and keyboard map used by the system change entirely when I switch to that desktop.

I have no idea if this is possible, but would really appreciate any advice please.

As far as I am aware this isn't possible.

That's a shame, would really help me out.

Can it be configured so the keyboard map changes, at least?

As far as I know, it can't be, however as an alternative I believe it can change when you press certain shortcut keys.