I\'m trying to enable spell checking on a RichTextBox in a small WPF application. Most of the documents for the application are in danish. I would prefer to use natively WPF
Please see this blog post from the WPF team that elaborates a bit more.
In configurations where only 4 languages are supported, you just need to set xml:lang correctly - I don't believe that you need to installe any additional lang-packs.
On platforms that support additional languages, the OS needs the underlying platform support to be enabled first. This support can be enabled by installing the corresponding Feature On Demand package (FoD) package.
The KB article linked above doesn't elaborate on precisely how to install the right FoD package. You can do this in one of the two ways -