You did clarify latter a bit, but this cannot stand unchallenged. TDD and tests solve different problems from types and so are valuable for that. Tests assert that no matter what you change this one fact remains true. Types assert that you are using the right things in your code.

I don't think it is lack of types at fault for untyped languages liking TDD (though I miss types a lot). I think it is there is no way to find out if functions exist until runtime (most allow self modifying code of some form so a static analysis can't verify without solving the halting problem). Though once you know a function exists the next step of verifying the function (or an overload in some languages) exists does need types.