for me as a programmer its very convenient to use a US keyboard layout. In fact I got so used to it that its hard for me to go back to the localized layout of my native language German. What I miss though are Umlauts.
I would like to create some X mapping allowing me to use the fn keys of my keyboards in combination with another letter key 'a' to for example create the character 'ä'.
I have tried other methods which are all just too annoying. I also don't want to switch the entire keyboard layout between US and German just because I need four or so additional letters.
Anyone having an idea on how to do this? Any idea if this could work outside the X server as well?