Io is worth learning just to see what a clean prototype-based language feels like. It'll probably improve your understanding of Javascript.
I wish JavaScript's prototypal features were more like io's, or even Lua's. io was the first language I had seen where I really grocked prototypal inheritance.
I miss NewtonScript for its version of prototype inheritance, but was never fond of the syntax.
I was hacking Io at the C level years ago, and I understand prototype inheritance just fine. I'm far more interested in Scala and Haskell, thanks.
That's a rather ignorant statement to make.
That's a very presumptuous response. I'm very familiar with lisp, scheme, perl, python, php, ruby and javascript. After moving to scala last year I realized that I'm a lot more productive in a good statically typed language than I am in any of those.