Desktop: no way to install spellcheckers/hyphenators other than the preinstalled English ones

[marcusmueller]

Describe the Bug

Stumbled upon Collabora Office today. Pass/Fail test for any office suite for me as a non-native English speaker is whether the text processor can do what MS Office could do 1997, and Google Docs still fails at today (LibreOffice passes, but has the worst UX for this):
Hyphenate a document in a way that doesn't require manual entry of hyphens.

Steps to Reproduce

1. install Collabora Office via Flatpak
2. click through the extremely annoying slideshow that can't be skipped
3. new document
4. Type "Das sind des Donau-Dampfschiffartskapitäns seine Erfahrungswerte: Wir werden die Buchhaltungsexperten nicht davon erlösen können, Nachtragshaushaltsdetailfehler auszumachen, und in Angesicht der Finanzmarktlagetrends ist dies auch kaum wünschenswert."
5. Go to review tab and try to get Hyphenation working

Expected Behavior

Hyphenation of German text working, ideally while typing!

Actual Behavior

Hyphenation for German is not even an installable option

Screenshots

this is how the document looks like after typing:

This is where I hoped to find the option to choose German:

But it's not there. There's also no option how to install more language packs (I have the necessary language packs for the libreoffice on this machine, so that's technically possible, probably).

Also note that the "Select language" Modal is far too small even just for the English choices; this feels very Windows95 as dialog, as it's not even resizable.

Desktop

COOLWSD version: 25.04.9.2(git hash: 76dd790)
LOKit version: Collabora Office 25.04.9.2(git hash: e3742eddf2)
OS: Fedora 42 x86_64