If you have version 5.3.0 of the XMLmind XML Editor, then you can download and install a German dictionary package.

To do so, download and install the package per your operating system:

Operating SystemInstaller to downloadSizeHow to install
WindowsXXEGermanSetup.exe1MBRun the installer. It will do all that is needed.
Mac OS XXXEGerman.dmg945KBRun the installer. It will do all that is needed.
LinuxXXEGermanSetup.tar.gz933KB
  1. Decompress and extract the installer in some directory.
  2. In a Terminal, do
    sudo ./installxxefrench