I am sure that there are other languages that I can (perhaps - separately) download and use, however I can’t seem to find it using the help sections you have. Ideally I would need only the French language - Polish would be great, too!
French is built-in to my English version. You need to define the language of the paragraph or document first, lets assume it for a selection that you have made, possibly all (Ctrl+A).
Tools > Language > For Selection and you don’t see French so click More…
In the dialog that opens there is a drop-down list headed Language. Select French (France) or dialect you want, but make sure it has a green ABC tick next to it. OK
I thought I had seen a Polish dictionary on Extensions web site but cannot find it now.