There are two things that always bugged me about Chomsky and his 50-year run dominating the field of linguistics. There are plenty of things that didn't bug me, including the fact that he really knew his grammar, and that he was against the Vietnam War; however, these things just tended to entrench his rule and kept people from seeing the more obvious problems with his philosophy.
Yes, so the first one was that he was wrong. He talked about universals, and he framed them in terms of restrictions, and worse yet restrictions that we have access to, as if being born into humanity is like being put into a genetic, biological straitjacket which now demands that we see things hierarchically, construct languages in certain ways, etc. Yet history and even modern textbooks are full of these alleged "universals" that haven't panned out. All languages have subjects? No, lots don't. All languages pluralize noun phrases at the phrasal level? No, many don't have a phrasal level, or even a concept of "pluralize" that we could call universal. All languages have ways to count? No. All languages express basic human relationships like father, mother, etc.? No. All languages have recursion?
This last one seemed to be Chomsky's last stand, and I have to stay out of it, partly because recursion could conceivably be defined so broadly that all languages must have it, but also because the one guy who disproved even that (pointing out that the Piraha of Brazil don't have it) - well, he could be right or could be wrong, depending on what you figure out after you put six or seven years into learning their language. So the jury's still our on that, but even if everyone had recursion, would that be a universal? And if so, what value would it have; what would it prove?
The second thing that really, really bothered me about Chomsky was the language. It's true that all academic fields have their own language, and that in many cases this language is incomprehensible to laymen. I accept that. But after reading enough Chomsky, and the work of his followers and those who have adapted the language of argument in this case, I've come to several conclusions. First, framing it negatively ("access" to restrictions) is the wrong approach to finding universals. Second, you don't have to get very deep into it before you realize that you've lost touch with the basic workings of the human brain. The whole point, after all, is to replicate the way the average person sees and explains the language. I think it's good to keep that in mind every step of the way. My international students are fond of saying that English grammar is very hard, very twisted, extremely hard to comprehend and master. Actually I think they're wrong about this. It may be extremely different from theirs, and may have patterns that are hard to get used to. But in its fundamental nature it's not made to confuse, it's made to be mastered by as many people as possible. And therefore the language we use to describe it should resonate with what we did as children to figure it out.
We in the native-English-speaking community learned our language as a basic part of our environment, much like mastering tying our shoes (which was common in that era) or riding a bicycle (also a common thing that kids did). We never really made a conscious choice to learn it, but we did have several years to listen to it before we felt pressured into actually using it, and even then our parents knew most of what we wanted without the words (they were in the habit of giving it to us anyway) and they greatly encouraged all our speaking efforts. But the intensity with which a two or three-year old attacks the organization of language shows that they really are developing a system, a machinery, an explanation for everything that happens. If there is such a thing as a "deep structure", native speakers ought to be able to say, basically, yes, that makes sense, that's how I do it, and that's how I've always done it. Yes indeed, that's the system I used to explain it and set up my own language production machinery.
Now I find that when Chomsky starts talking about deep structure, and c-command and hierarchical structure of language, he's already losing me. I'm not convinced that those trees adequately or clearly represent what is going on in my head or that of others. If there is a universal grammar that is calling the shots or determining how this system works, I have trouble seeing the separation of universal restrictions from local parameters that determine things such as, where do we put the preposition, or how do we show singular/plural in this particular construction. Chomsky has been unable to convince me that there is anything universal in the series of processes I use to construct a sentence.
Chomsky's whole point was, having postulated this universal set of rules or restrictions on all language learners everywhere, he should be able to show how our common humanity led us to construct things in certain common, universal ways. It seems to me that if we had found any of these, we would have been able to recognize them, and say something to the effect that, yes, that makes sense, I con see why that would be true for everyone. When I say that grammar has to be learnable and understandable, I think you should say, yes, that makes sense, if a culture is going to pawn this system off on many generations in a row, and expect them to grow up and use this language in this group to function and get what they want, then their grammar is going to have to be learnable and understandable, or else their system is not going to hold up over time. And you should recognize this and realize that, yes, no matter what language you grow up in, generally you can learn that language, and function in it, and the progression where you listen for a year or two, and you start speaking, and pretty soon you're making whole sentences: this progression is about the same, no matter what language you're born into. And you don't have to be a genius to become reasonably fluent in your first language, in a reasonably short period of time, with a working system that constructs verbs correctly, and puts prepositions in the right place, etc.
Now there are a number of things that I often say about this process, and I've noticed which ones resonate and which ones are going to be a little tougher to prove, because they are not so obvious. Let's play along as I start with the easier stuff. To me it's all an open question but I have no doubt about what I've written so far, and I'm willing to accept arguments about virtually everything. OK, here's the first. Children make hypotheses about how things work, and they actually test out the data (what they hear) against the system as they understand it, in order to come up with the best possible working explanation for how things are. Therefore language is, to them and to all of us native speakers, a system of best-possible-explanations for how things are made and how they are done. Our system can be described partly like this: "We start out with a subject...the subject is generally a noun and is marked as a noun....it hcan have several words but if it does, a determiner comes first and all adjectives come before the noun...adjectives are words that describe nouns...then, you have a verb...generally sentences have subjects and verbs...generally you mark both subject and verb as matching each other...
Now you may find fault with my system as I've begun to construct it, and you can certainly find exceptions, for example sentences that don't have a subject, or sentences in which some verb acts as a subject. But my point is this. My system as I construct it should make sense to the vast majority of native-speaker-readers, most of whom should recognize the machinery of their own system in the words I've used to describe it. They should be able to recognize fundamental truths of our system (like determiners, articles, subject-verb matching) though they may use different words for them or understand them slightly differently. The biggest difference between different speakers of the same language will be in relative importance of different rules in constructing a language; you will often understand something I say, yet disagree about when it should be said or how important it is in the grand scheme of constructing this language.
But in any case it will resonate with you at every step of the way, and you should find yourself agreeing by saying, yes, that explains why we do what we do. And the question is, why do we do it this way? And my main point is, the answer, "because all humans do it this way every time" has not proven to pan out very well, whereas the answer "because we in our community have done it this way for years, and taught our children to do it this way" is a far more accurate explanation, in almost every case.
Now, if linguists can stick to this principle - that what we explain should always make sense to native speakers, then, we can stay true to the science of what we are doing, and also stay true to the fundamental purpose of linguistics, which is to explain why people use language in certain patterns and why science can explain changes in these patterns over time. We can say that there is a reason for observable human behavior and that all of us, native speakers of a language, have similar or common understandings or perceptions of how things are done. We can, finally, I hope, find out what is truly universal in this set of sets of rules, and know when we recognize it: something that all people, everywhere, do, because they are people. If there's something universal, let's find it, identify it, put it on the table. Because it matters, and because, finally, Chomsky and his followers will back off.