Question: Situaltion:

* I have a windows forms application which is currently only available in german for the end user
* There is an existing userbase which gets auto updates
* The application is already translated to english in our dev branch
* The apps main window is a ribbon form

Now I want to allow the user to switch between german and english (more languages will follow) and I am thinking on how to implement the option to change the language.

I thought about a ribbon group with little flags for every language available.  

The flags are greyed out except from the current selected.  

The ribbon section shows up to six icons and more are shown only if you extend the section (ribbon standard)  

Of course the current selected languge, the current users local are always shown

This seems to be a simple approach to me but than again I have never seen something similar in a windows forms application so I am wondering if this is a good idea or if I should use a different concept.

Answer: 
Using a dropdown of languages positioned appropriately on the form of course would be ideal. One - you can just add more languages to the dropdown in the future. Two, you can display the language in the dropdown in native script. Three, assuming you add 20 languages in the future, scroll on the dropdown won't be an issue, whereas content would scroll inside the ribbon.
It can also be done this way
A language icon could be placed somewhere on the top bar, On mouse hover (or on click) a language drop-down or a small div to place the other language flags. When the user selects a particular language flag, it replaces the previous one.This would save space on the page and is also user friendly.