Add language pack for spell checking in LibreOffice

I have Manjaro Gnome installed and would like to add additional a spell checking languages to LibreOffice (and also the whole OS if possible). I searched in forums and found this post suggested installing the according hunspell package for the desired language. I installed the hunspell language packs via pacman but in LibreOffice I still only have the spell checking options for English (US and UK).

Which language packs did you install?

I installed the package hunspell-de. The package hunspell was already installed by default.

Some of the Libre office packages must be downloaded from libreoffice web and installed as an extension - (or something like that).

I also tried that. Below you can see the screenshots of the LibreOffice settings and also the installed extensions. So I have German installed as a system wide language via hunspell-de and also the German LibreOffice extension, but still only en-GB and en-US is available as a proofing language.