Comment by weavejester

I was being glib, so let me expand on what I said a little.

By 'constraint' I mean something the language disallows or at least discourages. Constraints in software development are generally intended to eliminate certain classes of errors. Static typing, immutability, variable scoping, automatic memory management and encapsulation are all examples of constraints, and represent control that the language takes away from the developer (or at least hides behind 'unsafe' APIs).

By 'expressiveness' I mean a rough measurement of how concisely a language can implement functionality. I'm not talking code golf here; I mean more the size of the AST than the actual number of bytes in the source files.

Adding constraints to a language does not necessarily reduce its overall expressiveness, but static typing is one of those constraints that typically does have a negative effect on language expressiveness. Some will argue that static typing is worth it regardless, or that this isn't an inherent problem with static typing, but one that stems from inadequate compilers.