How to switch the KeyboardLayout for all Application at once

From the research I did, I found no way to do this through windows; I think it is hard-coded.

However I found an application that provides this behaviour: Keyla. It is even open source, so you can be sure there is no funny business going on.

Switching the keyboard layout for all applications simultaneously is the default behavior in Windows 8, so that might be a reason to upgrade.