When I'm making a post, I can choose the language is made on. But there are so many. No one speaks so many, so I'll have to scroll through in order to find mine. Is it possible we can filter this list so there will be only the languages we can speak?

I don't think it's a feature used much at all, just ignore it. Unless you post in a language specific community it'll be English by default no matter what (if any) you choose.

You can select the available languages on the website of your instance. Summit has a section like "website settings" in its settings, but the language selection is not in it.

Will it? You don't have to set your own default language first? I guess that's kind of useful, though it seems like it could be problematic.

I know its not that important. It would just be nice

Doesn't seem to work well on lemmy.world

Then the feature should be removed. Having it, but making it barely usable is a bad solution.