Depends. APL is the OG. Try a few and see what you like. If you learn one Iverson language, it's pretty easy picking up the others.

Here's a gentle guide to APL by the same author (me):

https://xpqz.github.io/learnapl/

Dyalog APL is likely the best supported in terms of tooling, debugging etc. If you're looking for static typing, you're in the wrong place.