Haskell is typed lambda calculus and an amazing amount of syntactic sugar. One of the ten or so "aha!" moments of learning Haskell is realizing that so much of the language boils down to just \x -> let {...} in case {...}.

Which probably wouldn't be a bad way to teach Haskell, perhaps -- once one gets the general underlying form, understanding the rest is mostly just learning how the rest maps to that form.