To get the desired behavior, edit /usr/share/X11/xkb/symbols/nokia_vndr/rx-51 (as root, so be careful!), .... SNIP .... EDIT: just looked up the Polish entries in rx-51 and found that they don't have period and comma where the German keyboard has them, so my instructions are good for the German, Portuguese/Spanish, Swiss, Italian, Czech, and Nordic versions only. For a general how-to see the wiki on keyboard remapping!