What this argument doesn't account for is that there are universal rules that underlie all human languages -- even so-called "idiolects". When languages mutate, as they do constantly, they do so only within these rules. I'm speaking here of X-bar theory, bare phrase structure, and so on.
In effect, we're hard-wired to process language, and so are constrained by the limits of that wiring. A mutation ("mistake") that violates these rules will not 'stick', because the resulting language would be unintelligible to humans.
In effect, we're hard-wired to process language, and so are constrained by the limits of that wiring. A mutation ("mistake") that violates these rules will not 'stick', because the resulting language would be unintelligible to humans.