In T59832#637121, @Manybubbles wrote:

The problem here is that the language rules are customized for the wiki's language. Elision is handled in French but not English.

That is the crux of the original problem.

I wonder how much harm it would be to just add it to English (and maybe other languages) as well. Here are the term prefixes that would be removed:

I don't think this is a great idea. We could pick some low-hanging fruit by adding, say, some French rules to English-language processing, but should we also add something for German, or Spanish, or Ukrainian? Do we only add them to English, or also to Welsh?

Which "foreign" rules will interact poorly with which native languages? Hard to say without a lot of work. It would also require unpacking the monolithic analyzers we have to enable it, and some of the third party analyzers can't be unpacked, so they would be treated differently, etc., etc.

However, the current language analysis for English splits on apostrophes (which is actually not always great—searching for don't can match Don T. and Donal T. and donning T-shirts—though instances of "don't" are generally ranked higher unless you do a lot of work), so the original problem of searching for Arc-en-Ciel and finding l'Arc-en-Ciel is working correctly now.

However, because the English analyzer doesn't drop French stop words, searching for d'homme or l'homme will not find all instances of homme.

I'm going to close the ticket, because the main issue is working now and I don't think we're going to enable any more French-specific analysis on any non-French wikis.