Thanks, Walt,
I am running Affinity Publisher 1.9.1 on Mac OS Big Sur 11.3 Beta on an M1 MacBook Pro.
I think I got through the issues, that made me almost tear out my hair the other day, and will describe here how I did.
1) Check: System preferences for spelling in keyboard->text to select language automatically
2) In System Preferences, Languages and region - Check: Danish as primary system language, English secondary
3) I have downloaded and added the Danish dictionary to the Spelling folder and restarted. (as suggested elsewhere. I am afraid that it is necessary, even though the built-in dictionary is just fine and works perfectly with all other apps, as far as I have tried - for ages)
Now for the fun part:
4) Start Affinity Publisher
5) make New Document (I use A4)
6) Go to palet Character->Language
Now it says: Spelling: Unknown (en-DK):
(Apparently it gets confused if the Application language is not the same as the system language… )
* result: Text is not spelling checked.
7) Change Language to Dansk or Dansk(Danmark)
Then it seems to work, as shown here.
A bit tedious to do this every time, though, so I will likely make a template for next time. (and keep this around to remind me how to do )
All other apps I use automatically pick up the language correctly, so if Affinity wishes to have international customers, this is a good place to enhance the functionality.
One thing I need to mention, is also the Spelling dialogue, which in Publisher looks like this: but in other apps look like this. Do note the last line, where you can change language. So much easier than to hunt for the correct place hidden somewhere.
I hope this will also help others in the same situation 🙂