I should have also mentioned my experience with Wolfram Mathematica. That introduced me to functional programming before I even knew what that was. The syntax is different, but the underlying concepts are the same. To some extent, you can play around with Mathematica in Wolfram Alpha.

Scala should also feel familiar to those who’ve kept up with JavaScript’s slapdash efforts to become more functional (a sequel to JavaScript’s slapdash efforts to become more object-oriented).