I have a multisite which shares extensions, but not content and images.
I have the Fabrik Forms/CCK component installed which I am using for a large database of user profile records which are input in a multipage form. If the form is only partially completed, Fabrik displays a warning message to the logged-in user when opening the record for editing.

Question: I need to set up a language override to change the text of that warning message. Fabrik stores its front-end language ini files within the /components/com_fabrik/language directory, not in the standard Joomla /language directory.

I only want this override to apply to one specific slave site. I'm not sure how to go about setting this up? How do I implement site-specific language overrides within the JMS platform?

I have set up an override using Joomla's language override feature, but it is saving it to the /language/overrides directory in the master site, which I assume will make it apply to all sites, since the language directory in the slave is symbolically linked to the master.

I'd guess this also applies to overrides for other components, which also rely on files in Joomla's /language/overrides directory?

Thanks!

As you have identified, the joomla overrides saves the content into a directory like
language/overrides/en-GB.override.ini

Effectively, if this directory is shared with a symbolic link, it is the same for all the slave site.
If you replace the sharing of /languages by a physical copy, you will be able to have different content for each slave site.
The potential issue will be related to the update and also in case where you install new extensions. In effect, if you make a physical copy, you will have in the future to synchronize manually the language directory in case of changes.
So I don't recommend this solution.

I think that it is possible to create a specific /languages directory inside the components/com_xxxx directory but I don't think that you can have a subdirectory overrides processed. Up to you to test this hypothesis.

Another solution would be to override the /templates/html/com_fabrik/< Your template> to add the reading of an additional language file.
So that, this new language file could be based on the site ID.
This solution requires to change each template file used by fabrik (or at least the one in which you want to override some keywords.

Thanks Edwin — the last solution using a template override with a specific language file seems like the best possibility for this site.