Ask HN: What programming language should I learn?

TLDR: I'm looking for a new language that's different than most that's also usable for building something useful.

For context: I consider myself an experienced programmer, I'm well-versed in Ruby and JavaScript, built massive projects in teams and on my own.

I learn languages that have roots close to C relatively quickly. That is, if I have to fix something in a Python repo, I probably can.

I also enjoy learning human languages, and after a while there are patterns, learning the basics of another Latin language is pretty easy.

I'm looking for the Swahili and the Japanese of programming. Something completely different, that will expand the ways I'm thinking about programming.

I don't really see much benefit in learning Swift or Rust in that regard.

I previously gave Clojure a try, that was a pretty good fit, but the JVM / ecosystem put me off.

It's important that I also want to be able to build something fun and hopefully also useful using my new knowledge.