Get the newest Linux distribution. Mandrake 8.1 or RedHat 7.2 or 8.0 work fantastically with regard to internationalization (which could not be said about previous distributions). If locales are not installed, you must install them. The GNU C Library comes with a locale database, which you should have on your system. Upgrade your glibc. Troubleshooting of older versions of XFree or KDE is insignificant in my opinion, as the systems get better and better and people install newer versions. You may find almost any xmodmap file in the GNOME directory in (SuSE) /opt/gnome/share/xmodmap (with standard ISO8859-1,2 and other definitions). To switch between the keyboards, use right Alt. Slackware has a very good databse of xmodmap maps in /usr/share/xmodmap. Use the command: locale -a to see all the locales.
If you want to list the current keymap table, issue the command: xmodmap -pk | more
The xkeycaps program is a sort of graphical front-end for xmodmap. Start it and see which numbers mean which keycode.
To make the mouse buttons left-handed, use a command: xmodmap -e "pointer = 3 2 1"
To remove the CapsLock and change it to a control key, write this in your Xmodmap file:
remove Lock = Caps_Lock keysym Caps_Lock = Control_L add Control = Control_L