> programming languages are <i>really easy to learn</i><p>> For evidence of how easy it is to learn programming languages, one of the authors of the current paper has, over the course of his life, learned 18 distinct programming languages. His father, a physics professor, claims to have used 20 and 30 programming languages. A quick poll of engineers at Lucid Software showed that this was not unique, with all of the engineers having used at least two programming languages, and the majority having used somewhere between 5 to 20.<p>I'm curious as to how different the languages that they're referring to are.<p>Python, Ruby, Perl, PHP, C, C++, D, and Java are all really similar to each other relative to the differences between them and Coq, Haskell, Lisp, Erlang, Prolog, Io, Spiral, FORTH, or Chapel.