I’d like to play with an array language because I’ve never used one. I don’t want to pay for it; this is just for fun and as an experiment. I also want to run it locally in a shell, writing it in a local editor, not working in a web UI. And while popularity isn’t everything, and none of these are exactly Python levels of widespread, I also don’t want to find myself learning a cool one along with 3 other people in the world and then find out all other array language programmers do things completely differently. (Analogy: I don’t want the equivalent experience of picking Haskell as my first ever PL.)

This topic tends to bring up a few, like APL itself, J, K, and BQN. Given those (soft!) constraints, what’s the one I want to start hacking around with?