Chris Okasaki wrote such a language. One of it's features was mandatory indentation (like python). Why mandatory indentation was effective at making a language learn-able, he didn't really know for sure, but he suspected it is because there is less visual noise.<p>If you want to make a super easy-to-teach, I suggest you try the following:<p>(1) Mandatory indentation. This is one of the most influencing factors.<p>(2) As little syntax as you can afford.<p>(3) An interactive loop. It makes Tinkering easy.<p>(4) A simple, probably dynamic, type system (numbers, chars and functions are probably enough). If you go the static route, there is no other way than Hindley-Milner based type systems. They are quite complex and their paranoia annoy some students, though.<p>The closest I can think of right now would be a scheme without parentheses, like in <a href="http://www.genyris.com/" rel="nofollow">http://www.genyris.com/</a>