I certainly don't think I've mastered any of them - even the languages that I use every day. But I can write real-world, useful programs in all of them. The 's

I certainly don't think I've mastered any of them - even the languages that I use every day. But I can write real-world, useful programs in all of them. The 'superpower' that the book gave me was a set of tools to think about computation in a language-independent way. Once I had that, then every new language was "oh, here's a nice syntax for doing something I already know how to do in Scheme". The new languages I learned were from a variety of paradigms - functional (Haskell, OCaml, R), object-oriented (Java, Python) and array-based (Q, Matlab). I haven't learned a logic-based language yet, but I've written an evaluator for one (section 4.4 of SICP) so I don't expect picking up Prolog to be difficult, if I ever choose to do it.