Problems with hyphenation and long lines

[Soft Rabbit]

When I write in Danish, lyx cannot generate hyphenated pdf-files. Eventually I found out that when I changed language to English in Document > Setting > Language, hyphenation works. (But, to have spelling in Danish to work, I had to switch back to Danish.) I have attached two lyx-files that show reproduce the problem. The only difference is:

$ diff example1.lyx example1-error.lyx
10c10
< \language english
---
> \language danish
70c70
< \quotes_style english
---
> \quotes_style danish

When language is Danish, hyphenation does not work.

Description: Ubuntu 22.04.3 LTS
Release: 22.04
apt-cache policy lyx
lyx:
  Installeret: 2.3.6-1
  Kandidat: 2.3.6-1
  Versionstabel:
 *** 2.3.6-1 500
        500 http://archive.ubuntu.com/ubuntu jammy/universe amd64 Packages
        100 /var/lib/dpkg/status