Ask HN: Which language is easiest to get started with functional programming?

Biased recommendation: Try racket https://racket-lang.org/ It's not pure functional, but the preferred style is to use mostly functional constructs. (But you can cheat when it get's too difficult or you need some extra speed.) (And you can download packages like Qi that enable a new language inside Racket that has more support for functional style.)

(Most Schemes have a similar mostly-functional style, so you can also try one of them.)