I use English keyboard and need to type some German letters from time to time. So I defined
(global-set-key [?\C-\;] (make-sparse-keymap)) (global-set-key [?\C-\; ?A] [?\x08C4]) ...
to insert "ä", etc. It used to work for years, but it doesn't work with my current GNU Emacs 23.1.1. I realize that using characters hardcoded as numbers is no good idea, but it helped me to work around encoding problems (only this worked fine on Sun, Linux, and Windows even with shared filesystems).
What is the best way to define keys for inserting special characters in Emacs?