The "Slur filter" is a server setting. The filter makes use of a "regex" (a text matching algorithm) to automatically remove any text that matches those words. An admin needs to explicitly set the rules for that regex. The regex does not take language into account, it is a simple text matching algorithm.

The box is in the Admin settings page and looks like this:

I know that lemmy.ml makes use of a strict set of regex rules. The translation of the french word for "late" matches an ableist slur in English, and so it is removed by lemmy.ml. ~~I am not sure about whether you can check regex for each individual server, but I believe that most instances don't filter that specific word out.~~

EDIT: Ah, I found out how to check the regex. You can check an instance's regex by going to the the URL https://{instance}.{TLD}/api/v3/site and looking for "slur_filter_regex". For example, for lemmy.ml you would go to:

https://lemmy.ml/api/v3/site