Minimal yet Optimal

Andrea Moro’s 2008 book The Boundaries of Babel: The Brain and the Enigma of Impossible Languages (hereafter Boundaries) can be best described as a book set on the justification and exploration of some of the more probing questions regarding the formal study of language in the generative tradition and its intersection with neuroscience. Moro, professor of linguistics at Istituto Universitario di Studi Superiori di Pavia, sets out to explore some of the recent developments in syntactic theory, particularly—as the title suggests—the possible and impossible forms of language. By examining what it means to have an impossible language, Moro suggests that we can understand more fundamental aspects of the mind and the brain. Boundaries is not a terribly heavy volume, but it does sit firmly amongst those works which seek to instill in their readers a deep curiosity for unexpected phenomena without skimping on the detail. All at once, the book serves as a hitch-hiker’s guide to generative linguistic theory, a primer in the philosophy of science, and a brief yet compelling look into the blossoming fields of neurosyntax and biolinguistics.

Overall, Boundaries was structured in a thoughtful way, as Moro was deliberate in his choice of conveyed information.  Concepts and ideas he introduces in the earlier part of the book become fundamental to later explanations of abstract theories and experimental methodology. He begins by orienting the reader with modern generative linguistic theory, a linchpin for understanding the crux of his argument: the shape of language structure. This is not an easy venture, as the last fifty years has seen a flurry of theories and theoretical models, which Moro manages to present in a relatively straightforward way. Moro has his work cut out for him, as often the study of language as linguists see it is far different from what the general population believes. Thus, the first chapter on generative linguistic theory is daunting, standing at 114 pages (it is nearly half the book!); however, it is necessary, and Moro explains these concepts with ease.

He begins the book by guiding the reader through issues in linguistics such as the syntax-semantics divide, structure dependence, and syntactic formalism. These are difficult topics to cover at length, let alone in a summarized fashion. As Moro explains, language is an elusive object, as we can only observe “how it behaves” and “what it can’t do.” He likens the linguist’s quest for understanding language by analogy to generating a set of principles for cooking; Individual recipes contain many similar steps, from which one could derive a set of “universal principles” that transcend any one dish and instead give a glimpse of the practice itself. In other words, linguists are seeking an understanding of the underlying mechanisms for language rather than any particular grammatical construction or rule. Moro uses this particular view of language to catapult the reader into Chomsky’s key insights into children’s acquisition problem concerning language, particularly why it is the case that acquisition takes place not on the surface qualities of sentences but principles which aren’t always explicit. For instance, when acquiring their language, children can only hear sentences in a linear fashion: that is, one word after the other. However, it is clear from sentences involving question formation and reflexive pronouns that language does not necessarily operate on a linear basis. Instead, the structure is hierarchical, with some words “dominating” others, like a pyramid stacked on another. Skilled with metaphor, Moro equates this to “a tapestry,” whose front reveals a clear image, but whose reverse contains a complex weaving of threads with only a partial pattern. This seems, as Moro points out, to be the case for all languages worldwide. Why is the structure of human language this way? Moro seeks to explore this question along with others regarding grammars that are possible, i.e. those that conform to universal principles of language, and those which do not. This is the crux of the argument in Boundaries, as Moro’s goal is give some tentative answers  to the question above by reporting on two previous experiments from he and his colleagues concerning the nature of syntax in the brain.

In these experiments, Moro sought answers to two fundamental questions: a.) is syntax a mechanism that has its own separate operations in the brain; and b.) can structure dependence be observed as a process? These questions may sound easy to get at, but when it comes to the brain, nothing is easy. First, the brain is constantly acting, and often in non-linguistic ways. It is constantly paying attention to the environment, regulating internal mechanisms and organs, and fixing memories, among other activities. Thus, picking out language amongst the noise is a tedious process, done by a battery of tests and algorithms that try to highlight particular areas of brain (and indicating that other active areas during a neutral condition can safely be subtracted from the picture.) Further, as any linguist would point out, syntax is not entirely separate from other aspects of language. This is true in the cognitive and the biological sense, as many neural structures in the brain related to speech are grouped in similar areas. Thus, there is a dual problem, one which can be solved by, as Moro cleverly describes, tricking the brain with errors. For the first experimental question, Moro and his colleagues examined different groups exposed to differing kinds of linguistic deviation.  Discerning syntax from phonology and semantics seems at first impossible, since syntax inherently operates on lexical items that carry this information. To get around this, Moro and his colleagues used two shrewd ways to isolate syntax. First, they used nonsense words (a la Jabberwocky) to make it so that the meanings of words did not interfere. So, a participant in the experiment would see a sentence like the bonf lunked the grival, which doesn’t have any discernible meaning. Second, they used sound combinations that are not part of the native language of the participant. For English speakers, this would be similar to changing the previous sentence to the bfonf tlunked the sgripf (of course, Moro’s examples are much more clever than mine.) These quite obviously seem like sentences; however, if you switch them it becomes clear that they are ungrammatical, as in bfonf sgripf the tlunked the. Despite not knowing the meanings of these words, it is clear that no English sentence would be structured in this manner. Thus, we make it so that the syntax is the only meaningful aspect of the sentence. When participants were exposed to a set of sentences in this fashion, there was a limited area of the brain that was consistently active: cortical and deep portions of area 45 or Broca’s area, a familiar name for those in linguistics and psychology. This part of the brain is shown to be associated with syntactic processing. This seems to indicate, then, that syntactic errors can show that a separate part of the brain is attempting to figure see the trees for the forest, so to speak.

For the second experiment, the participants instead are exposed to a different set of conditions: learning possible and impossible rules. In this instance, this means structure dependence vs. linear rules. Participants were exposed to a foreign language that operated on structural principles, such as an embedded clause’s verb maintaining its position, and rules that relied on an arbitrary linear position, such as not being put in the fourth position of sentence no matter what. Do these impossible rules activate the same neural nets that the possible, natural rules do? Well, it turns out that they activate differently. The results of both experiments, Moro argues, are “surprising” as there wasn’t an “a priori guarantee that that these data should ever lead to a convergence [of theoretical linguistic and neuroscientific results].” (p. 178). He shies away from saying that linguistics and neuroscience are going to be unified or “isomorphic;” instead, he indicates that it is enough for now that they are each generating significant and compelling mysteries for the other. As Moro says, “we may need to go through radical changes in order to look at both language and the brain in a way that unifies them.” (p. 178). I share his sentiment that this unification seems far off, though results such as those presented in Boundaries certainly inspire hope.

Boundaries of Babel is a wonderfully engaging book that will leave the reader with a healthy curiosity. It isn’t a groundbreaking work, and Moro doesn’t claim it to be. Rather, it is a book that is here to spark interest in the reader about the fundamental nature of language, particularly the structure of language as it is realized psychologically and biologically. With his creative use of metaphor and analogy, and a careful attention to background information, Moro undoubtedly will leave the reader with something new and perplexing to think about. At the same time, those with a background in linguistics may find Boundaries dull, as it covers much more conventional linguistic than neuroscientific ground. Still, the section concerning his previous neuroscientific experiments can provide a brief glimpse into the methodologies of performing this sorts of research, as well as the difficulty in interpreting it. For neuroscientists, it perhaps will seem to be a book about linguistics rather than the brain, considering there is only a relatively brief section dedicated to it. However, Moro’s goal here is to show a place where the two fields are coming together, rather than providing the yet far-off solutions to the questions he’s proposed. With that, he does a wonderful job, and Boundaries of Babel leaves me with the optimistic curiosity that Moro was undoubtedly hoping to instill.

Buy Moro’s book here: https://mitpress.mit.edu/books/boundaries-babel

The updated version (I reviewed the first edition) is here: https://mitpress.mit.edu/books/boundaries-babel-0