I'd say LISP, or Scheme or a language from that family would be the most orthogonal. With let, lambda, define, if, cons, list, and ( ) you can teach pretty much anything that you'd want to in an intro course. There's also no need for preprocessing directives or int main() and stuff like that which students just include but don't see a reason too.

In my intro CS courses, we did a lot of really cool things with Scheme: implement a Turing machine, implement a TC-201 computer, write a context free grammar, use recursion, write merge and insertion sort, implement adders, and tons of other stuff.

I had done Java in AP comp sci before college, but Scheme was great because I could cut the clutter and focus on the actual concepts in my program. It was a great class and I'd highly recommend you try it for your teaching.

I'd say LISP, or Scheme or a language from that family would be the most orthogonal. With let, lambda, define, if, cons, list, and ( ) you can teach pretty much anything that you'd want to in an intro course. There's also no need for preprocessing directives or int main() and stuff like that which students just include but don't see a reason for.

In my intro CS courses, we did a lot of really cool things with Scheme: implement a Turing machine, implement a TC-201 computer, write a context free grammar, use recursion, write merge and insertion sort, implement adders, and tons of other stuff.

I had done Java in AP comp sci before college, but Scheme was great because I could cut the clutter and focus on the actual concepts in my program. It was a great class and I'd highly recommend you try it for your teaching.