How do I add languages to the status bar pick list in LibreOffice Calc?

I am using Libreoffice 6.4.3.2 on Gentoo Linux.

I have built the package with the de en-GB fr nb l10n-language packs, but I have German as the default and interface language and that is the only language that appears in the pick list when I right-click on the language field in the status bar:

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Of course I can pick any language for which there are dictionaries installed when I right-click on a selection of cells, say, and choose “Format cells”, but this is more time-consuming and I recall that this used to be possible from the status bar. I thought perhaps that the Gentoo language packs were not being recognized by LibreOffice, but adding languages from extensions.libreoffice.org does not change what appears in the status bar, even after restarting.