On the Non-universality of Grammar

One of the strongest – or at least most important – arguments for the existence of UG is the logical problem of language acquisition. As presented, it takes the form:

1. Premise: Syntax is a productive, recursive, and infinite system.
2. Premise: Rule-governed infinite systems are unlearnable.
3. Conclusion: Therefore syntax is an unlearnable system. Since we have it, it follows at least parts of syntax are innate.

We will look at two problematic assumptions made in this form of the argument

The first assumption is that "we have it" – i.e. we are able to recognize any utterance as either grammatical or not. This is in essence very similar to the objection presented under the aside "Statistical Probability or UG?" In response, the author claims that any "statistical" explanation does not explain how we may recognize a sentence which is a very rare "type" – such as "John said that Mary thinks that Susan believes that Matt exclaimed that Marian claimed that Art said that Andrew wondered if Gwen had lost her pen." – as grammatical. But just because we may be imprecise in evaluating grammaticality does not mean that we cannot apply some simple "rules" that we have learned to such a sentence to see that it is indeed grammatical. The fact that if we were to change "Matt exclaimed" to "Matt exclaims," it would take extra effort to tell whether or not the sentence is grammatical further supports the idea that we assess grammaticality, rather than simply applying rules and knowing whether the sentence is or isn't grammatical. Note that this does not preclude the fact that people's brains have evolved to be able to make such generalizations well – that we are have evolved to be good at, to be predisposed to learning language. This, however, is a totally different claim from there being innate rules of language.

The second, deeper problem, is the assumption that grammar itself is a fixed, "rule-governed" system, or really a "system" at all. Grammar is simply a product of how we use language, perhaps even a way we describe how we use language. As an analogy, we may look to how parts of speech can be assigned to a nonsense sentence, and are thus defined by their use. And how we use language is fluid, malleable. What is grammatical is thus itself subject to change. Returning to the example of the long sentence above, we decide that the sentence is grammatical. This is true both in the first case, and especially in the case where we modify it make it harder to tell whether it is grammatical or not.