Fair enough. The article explained that poorly and made it sound as if there is a real contingent of psychologists who think that babies magically know grammar as opposed to learning it.

Given this reframing of the research, I fail to see how this study demonstrates anything, though. If the brain has special structures that allow humans to learn grammar, you would still expect to see the same pattern of "terrible, broken grammar -> mediocre grammar -> good grammar" that we see. We see the same learning pattern for things that the brain does have special structures for, such as... well... everything from sight to motor control.