[exim]

I'd personally prefer a language with static typing and ADT support, like Haskell or any ML-like one. But Racket (PLT Scheme) would be my second choice - and it is quite popular in overseas (USA) PL research circles. Also, I find it one of the most elegant lisp dialects out there.

[shriramkmurthi]

It's not an either-or. Typed Racket is a statically typed language, and students would be welcome to use it.