Quicker if you're writing shell scripts or a small single-purpose applications. Not quicker if you're adding to a codebase of any significant size.
Yes, IME it's still quicker.
OTOH, if you're using "codebase of significant size" as code for "big ball of mud", static typing certainly helps, but integration tests are the real lifesaver.
No. I mean when the codebase is of a certain size, new features require some thought and planning. Features may span multiple-modules. They may require partial or full rewrites or the refactoring of any number of sub-components to support the new behaviour. This means that you proceed carefully because you may not want to introduce regression bugs. This costs time. At that point, you're not limited by your typing speed as you may be putting in net 10 lines of code a day. There is just no benefit to dynamic typing at that point. Worse for dynamic languages, this is where improved tooling and static type constraints start paying extreme dividends.
Yes. And all equally true for statically typed languages.
Refactoring without tests is easier in a statically typed language, but still stupid. If you assume a decent body of tests, the benefit dissipates quickly.
If you prototype faster, as you usually will in a dynamically typed language, your design mistakes cost less. Since in large software systems I tend to find that the two biggest sources of bugs are a) errors in specification and b) poorly designed APIs, not obscure edge case bugs, quicker prototyping helps in large projects too.
And, if your design is solid, you can still achieve similar benefits as static typing by "locking down" your boundary code with asserts so that future development that interacts with that boundary code will fail quickly if it interacted with in the wrong way.
>At that point, you're not limited by your typing speed as you may be putting in net 10 lines of code a day. There is just no benefit to dynamic typing at that point.
This is fallacious. You're never limited by your typing speed in any language at any point. The cost of "extra typing" is cognitive, not a finger speed limitation.
The benefit of dynamic typing is more flexibility in the code you write (especially useful for writing frameworks and such) and quicker turnaround when prototyping because you do not have to prespecify as much up front.
