Symphony.

Do you have Nils’ lang_german installed?

You don’t need to install the German Language pack to get it working as the extension provides its own translations.

The extension enable-disable process must be a bit quirky.

There are some quirks related to extension handling:
http://getsymphony.com/discuss/issues/view/372/

Markdown Guide updated to version 1.3 on 28th of September 2010

Added localization feature built by Nils Werner (phoque). Currently includes only a German translation dictionary file.

Sadly not compatible with Multilingual Field Extension

I have updated this for 2.3 compatibility. Seems to work. Forked on Github and pull request sent to @wiseolman.

I've used @stuartpalmer's fork and have added the extension.meta.xml file, as well as updated the README file. Here's my fork on Github. Also, sent a pull request to the owner @wisolman.

I can confirm this does work with Symphony 2.3.