Libreoffice with Flatpak: Adding dictionaries for other languages

I generally write in either English, French or Mauritian Kreol.

I also use Libreoffice when I need a word processor or a spreadsheet (or, even, sometimes, a drawing software). Lately, I have discovered Flatpak (“The Future of Apps on Linux”) and Flathub (“An App Store for Linux”) and I am sold. Installing the latest version of Libreoffice from Flathub using Flatpak is a simple:

$ flatpak install flathub org.libreoffice.LibreOffice

I have noticed though that this command tends to only install the English dictionaries for spellchecking. I didn’t know how to install more dictionaries to Libreoffice so I asked on the official Flathub forum. And, fortunately, someone from the community pointed me towards the solution. The idea is to get some information about the Libreoffice installation:

$ flatpak info org.libreoffice.LibreOffice

LibreOffice - The LibreOffice productivity suite

ID: org.libreoffice.LibreOffice
Ref: app/org.libreoffice.LibreOffice/x86_64/stable
Arch: x86_64
Branch: stable
Version: 6.4.3.2
License: MPL-2.0
Origin: flathub
Collection: org.flathub.Stable
Installation: system
Installed: 686.0MB
Runtime: org.freedesktop.Platform/x86_64/19.08
Sdk: org.freedesktop.Sdk/x86_64/19.08

Commit: ddcb114395acb30f633a06fd065598ace0fbe4330c49a784a50911b0222f5f95
Parent: fa891c405f685f7859e2bb623b29db5cdb3e9e1d80d8c31f30a5d21edcc9a3eb
Subject: Update to libreoffice-6.4.3.2 (5a34256e) Date: 2020-04-16 18:32:28 +0000

Notice that the runtime is org.freedesktop.Platform/x86_64/19.08 which implies that org.freedesktop.Platform.Locale/x86_64/19.08 contains all the dictionaries. But, as pointed out by stbergmann in the forum,

The *.Locale extensions are special, in that flatpak by default only downloads that part of such an extension that matches the users current system locale, while the –reinstall hack unconditionally downloads all of it. There obviously needs to be usability improvements here, as this appears to be a common issue for users.

And this is the –reinstall hack he is talking about:

$ flatpak install --reinstall flathub org.freedesktop.Platform.Locale/x86_64/19.08

and, after a few seconds, the dictionary issue is cured. Now, in addition to English, you have French plus all the other languages. Enjoy :-)