The Most Important Idea in Computer Science links to two Alan Kay articles. The most interesting, "A Conversation with Alan Kay", "So the problem is—I’ve said this about both Smalltalk and Lisp—they tend to eat their young. What I mean is that both Lisp and Smalltalk are really fabulous vehicles, because they have a meta-system. They have so many ways of dealing with problems that the early-binding languages don’t have, that it’s very, very difficult for people who like Lisp or Smalltalk to imagine anything else."
"I feel like my answers are quite trivial since nobody really knows how to design a good language, including me."