[jpr]

I find that with a good, type-aware compiler such as SBCL, Common Lisp hits a really sweet spot on the typing issue. It catches a crapload of mistakes at compile time that would be runtime errors in Python (the language, incidentally the SBCL compiler is also named Python) and most other dynamic languages. The type-language of CL is also more expressive than anything else I have seen, featuring unions, intersections, predicates, subtyping etc. But most importantly, it stands in the background, and doesn't stop you from executing programs that don't conform to some preconceived notion of what typing should be like.