This foreword was written for a book by Liu Yuhong on the neurocognitive basis of language. It may serve also as a foreword for this website.

Foreword

By Sydney Lamb

As a young man back in 1964 I had become well known enough to be invited by Georgetown University to present a paper on Stratificational Grammar at its annual linguistics conference. Other speakers at that meeting included the great British linguist Michael Halliday and the great American neurologist Norman Geschwind. Both of these gentlemen had considerable influence on my subsequent thinking. This occasion was one of the first times that a neurologist had been invited to a linguistics conference. And now, more than forty years later, it is still rare for a linguistics conference to include any concern for neurology. This is unfortunate, for the joining of linguistics and neuroscience is actually of the utmost importance for the further development of both fields. Among the points made by Norman Geschwind at this 1964 meeting, the following still stands out in my mind:

I gather…that the status of linguistic theories continues to be a difficult problem. … I would wish, cautiously, to make the suggestion, that perhaps a further touchstone may be added: to what extent does the theory tie in with other, non-linguistic information, for example, the anatomical aspects of language? In the end such bridges link a theory to the broader body of scientific knowledge.  

At that time, in the early days of stratificational grammar, I was beginning to develop a network notation to depict linguistic relationships. Michael Halliday had already devised a network notation that he was using in his systemic grammar. His thinking, though different from mine in some respects, was compatible. It is especially important that he, like the Danish great linguist Louis Hjelmslev, stressed the need to be precise about linguistic relationships. Halliday’s network notation had just the devices that I needed to provide a clear distinction between syntagmatic (“both-and”) and paradigmatic (“either-or”) relationships, and I began using an adapted version of it. That is what became the classical version of relational network notation. I unveiled it to the public in 1965 in a lecture at the Linguistic Institute at the University of Michigan.

Meanwhile, as I was working with my then new network notation in the fall of 1964, I came upon a startling discovery: If all of the immediate relationships of a linguistic unit, such as a morpheme, are identified, the unit seems to disappear. It appears to be nothing other than a point in a network of relationships. This finding applies to any phoneme, any morpheme, any lexeme, even any syntactic construction. Of course, such a statement, is not only startling, it is actually a little misleading. A lexeme, or a syntactic construction, is what it is not just as occupier of a particular position within a network of relationships; what it is depends upon the other nodes and links to which it is connected.  
During the next few years, as I gave lectures in various places, people would often ask me whether the relational networks I was describing had any relationship to the neural networks of the brain. I had to answer that I did not know, since I had no particular knowledge of neural structures. I did have curiosity, however, about the brain and about neurons. In fact this curiosity was already developing during my student days, and during the oral qualifying examination I had to take as part of the requirements for my Ph.D. degree at the University of California, one of the professors asked me what I thought learning consisted of at the neurological level. I answered that I thought it was the strengthening of synapses – just a speculation at that time, but now that I have some neurological knowledge, I would give exactly the same answer.

Since people were asking me about a possible correspondence of some kind between relational networks and neural networks, I decided to learn something about neurons and neural networks. At that time I was on the faculty at Yale University. I located another faculty member there who taught neurophysiology in the biology department and arranged to have lunch with him. As he gave me an introduction to neural structures and neural interconnections I was amazed at how closely they corresponded with the networks I had developed just for explaining linguistic relationships. Of course, these two types of network are very different from each other in one respect, as neural networks are physical objects, while relational networks are quite abstract. But allowing for this difference, one can begin to see that relational networks can be implemented, through several intermediate levels, in neural structures. The essential properties needed for the proper functioning of relational networks are all there in the neural networks. After many years of further study I provided a detailed account of these correspondences in my book Pathways of the Brain (1999).

After this brief introduction to neuroscience I began to study the brain, and I offered a seminar on language and the brain to my graduate students. I also taught a course on Language and the Brain as a visiting professor at the State University of New York at Buffalo. Of course, at that time, the field of neuroscience was far less advanced than it has become during recent years. In those days, for example, the structure and importance of cortical columns was just beginning to be explored. 

It was not until 1992 that I began to seriously study neurolinguistics, when I undertook to teach a course on that topic at Rice University. The decade of the 1990’s was designated as “the decade of the brain”, and great advances were made in the neurosciences as more and more resources and manpower were poured into research. My thinking and learning were also making advances during this period, and in 1999 my book Pathways of the Brain: The Neurocognitive Basis of Language was published. This book is already out of date in some respects, but last fall (fall 2005) I presented an updated account in my neurolinguistics course at Rice University. The course was attended by Liu Yuhong, a visiting scholar from China. He has now written this book, for which I am providing this forward. As a result of Liu’s efforts, readers of Chinese will now have an up-to-date treatment of how language is represented in the brain and how linguistic processes operate in the brain. I congratulate Liu for his efforts and for his diligence and for the speed with which he has completed this project.

Why is a knowledge of neuroscience important for linguistics, and why is linguistics important for neuroscience? Let us briefly consider these two questions one at a time.

To elaborate on the thinking of Norman Geschwind in the above quotation, there are two main thoughts to consider (1) As long as linguistics remains isolated from neuroscience, it is isolated from science in general; it is the brain that provides the physical basis for the structure of linguistic systems. Without knowledge of the neurological foundation, theoretical studies of the nature of language are in danger of being speculative rather than realistic. Without such grounding a linguistic theory bases itself instead on unjustified assumptions and unrealistic notations. Perhaps the most pertinent example is generative grammar in its various forms, which dominated linguistic thinking during the past few decades. There is no scientific basis for its unquestioning adoption of rewriting rules as its primary notation. And the formulations based on this notation became so unwieldy that investigators concluded that a language system was too complex to be learnable by children and must therefore be innate. This thinking led to the absurd assumptions of a language organ and a language gene. What was overlooked was simply that the source of all that complexity, that seemed to make language unlearnable, was nothing other than an inappropriate notation. I have expanded on this point in Language and Reality (2004). 

But when we recognize the relevance of neuroscience, we see that language has a physical basis. That basis is the cerebral cortex. The structure of a person’s linguistic system is a network, and the cerebral cortex is a network. The nature of the network structure of linguistic information is elucidated by neuroanatomy and by knowledge of the operation of neurons and their interconnections. Treated in this way, linguistics turns out to have a firm scientific basis in biology. It thus becomes a part of the general scientific enterprise and not just an isolated field of humanities.

 Less clear at first glance is the other side of the story, the contribution that linguistics can make to neuroscience. Noam Chomsky once said, when the question came up of how generative grammar might be related to brain structure, that we don’t yet know how the brain works, so we are not ready to consider such questions. This is a widely held view. It rests upon the line of thinking that neuroscientists are the ones who will eventually figure out how the brain works, and all others must therefore wait for them to reach this goal before we can understand how the brain processes linguistic information. This seemingly reasonable line of thinking breaks down when we observe more closely just what neuroscientists do. They are concerned with the physical basis of the brain’s operation, with the molecular structures, with the ions and ion channels and their operation, with neurotransmitters, with the molecular changes that take place at synapses, and so forth. This is all very interesting and valuable information, and they are making great progress. But this type of work is quite different from that of figuring out how the brain processes and represents linguistic information, how it acquires and uses such information. Such higher-level functions are as much in the domain of the well-grounded linguist as that of the neuroscientist. 

To understand the problem more clearly, consider this analogy: Suppose instead that the problem is to figure out how a computer works, especially the problem of how a computer performs sophisticated operations like natural language processing. One might suppose that the answer can be provided by the electronic engineer, who understands the computer hardware – the integrated circuits and the capacitors and resistors and the wiring that connects all the components. Of course, such an engineer will not have the slightest idea of how the computer processes natural language, nor will he know how to go about acquiring such an understanding  – unless he also happens to have a knowledge of linguistics. No, to solve such a problem it is necessary to use the tools of linguistics. Similarly, a knowledge of linguistic structure and operation is necessary for exploring the problem of how the brain processes linguistic information. It makes no sense, therefore, for linguists to wait for neuroscientists to tell them how the brain performs such feats. Such waiting could go on forever, as long as the neuroscientists do not understand linguistics. And it has to be a sophisticated kind of linguistics, not speculative versions like generative grammar. 

Nevertheless, the limitations of their methods have not prevented neuroscientists from coming up with speculative notions of how the brain might perform higher-level functions like language processing. But we find, on examining such speculations, that they are quite naïve and way off base. Revealing examples can be found in the standard reference work, Principles of Neuroscience by Kandel, Schwartz, and Jessel (3rd edition, Elsevier, 1991). This large volume is full of valuable information about the anatomy and physiology of brain structures and about the consequences of various kinds of damage to brain tissues such as those resulting in various kinds of aphasia, but when it turns to questions of higher level brain functions it reveals the same lack of sophistication that we find in non-specialists. For example, Chomsky’s notions about how a child learns a language by testing the specifics of the speech heard in its environment against a genetically determined system of rules of generative grammar, are described approvingly in this volume on neuroscience. Perhaps even more revealing is the uncritical description given of a well-known but naïve so-called “neural network” model which is actually quite unrealistic in that its properties differ widely from those of the real neural networks of the human cortex. For example, it has only three levels, an input level, an output level, and between them an intermediate “hidden” level. But when we come to understand cortical function we see that almost the entire cortex is devoted to hundreds or thousands of hidden levels arranged hierarchically. If the authors of this manual of neuroscience understood how the brain works, they would have ignored or denounced that naïve model as hardly more than a computer toy.

Linguists, on the other hand, if they are practicing linguistics effectively, do have something to offer to an understanding of higher-level cortical function. They have become skilled in their craft by learning how to think about information structures and about how information is processed in various ways. Thus if a linguist frees himself from unwarranted assumptions and inappropriate notations and then examines linguistic information in its own terms, he can come to an understanding of fundamental linguistic relationships. Then, with guidance from knowledge of brain structures like the columns of the cortex, he can come to an understanding of how the brain learns and uses linguistic information. And it turns out that linguistic information is not essentially different in its cortical representation from other kinds of information. Therefore, the linguist has come to an understanding of how the brain processes information in general.

At least, that is what this linguist has done. The results of these efforts as of 2005, along with the relevant information from neuroscience, were summarized in my course in neurolinguistics at Rice University in the fall of 2005, and Dr. Liu has provided this account in Chinese. I join him in offering these pages to Chinese readers in the hope that they will find them illuminating.