Prolog. You'll discover what it feels like to have a language that actually does hard work for you (except string manipulation...), instead of having to guide it through every little detail.
Logic programming isn't actually that hard, and more people learning it will help move the state of programming forward.
I took a class that used prolog in college. It was so confusing at first. Then one day, I was doing an assignment with definite clause grammar, and everything clicked. It wasn’t just my understanding of prolog that benefitted, either. Suddenly I also internalized how regular expressions work.
I remember it distinctly because it was such a good, almost euphoric feeling that seemed to drop randomly on top of me.
When people say that learning a new, different language will give you benefits that carry over to the rest of your abilities, I remember that moment.
There is definitely a lot to be said for stretching your programming brain in new ways.
Logic programming isn't actually that hard, and more people learning it will help move the state of programming forward.