The Faculty of Speech and the Speech-Centers
The origin of man has been traced to Eastern prehuman groups. The origin of words has been traced to the mind through the faculty of speech. Just when our kind became human, no one knows. When man acquired the most important of his peculiar faculties, no one knows. This much seems probable: There was no common origin of language in the sense that from one primal tongue all others were derived. There are elements in the various known languages which are contrary to this view; even when all allowances have been made for transmutation under environmental pressure. Words, construction, and subtleties of meaning differ too widely in basic character to have sprung from a common ancestral speech. Conscious personality and group-variations of character at different periods under different stress must have moulded into families our primitive speech, if the mind is its mother. In later times but very far back, the earlier tribal tongues split into branches and otherwise became modified.
The fact that words issue from anatomical locations clearly fixed in the gray matter of the brain, does not argue that the speech-areas originate the words. The origin of the word is the idea of which the word is, among other things, the symbol. That particular area of the brain which made it possible for us to utilize the symbols of our ideas became fit for the purpose, first, through gestural relationship with the motor-centers in the brain. More searching inquiry shows that in all right-handed persons the speech-center is localized in the left hemisphere of the brain; left-handed persons have it in the right. Stone implements made by early man demonstrate that we have been right-handed for many thousands of years at least. Everything seems to indicate that the majority of our kind always was right-handed; and it has been proved that all right-handed persons have their word-areas in the left brain. This establishes the relationship between the right-hand, or the principal gestural organ, and the speech-area.
The thinker slowly and laboriously invented the instruments with which to define his thoughts. Habit gradually gave to the instrument so much the mastery of the mind that as modern man approaches adult life he is only capable of thinking by means of the instruments of his earlier racial invention. One may visualize without language, but no one can think in terms other than words. This characteristic of mental process determines true thought. Emotion is a very different phenomenon. Feeling finds expression in a wide range of terms and in various media. Certain emotions may be expressed better in music than in words—certain others in form—and still others in color. Again there are feelings that can not be expressed at all in words, for the mind harbors more than it knows and it has no clear symbols ready for use in certain of its conscious states.
This is not to drag in metaphysics; nor is it a theory made to fit certain isolated facts; but it is, rather, a deduction from physical facts. Clinical experience has shown that damage done to the speech-area may totally destroy the powers of thought while it leaves the emotional faculties seemingly undisturbed. It is clear, therefore, that words in their combinations are the instruments of thought; and that they are, in a limited sense, the masters or moulders of thought, if not actually the thought itself. Thus the ethical relations between language and thought may be much more intimate than is commonly suspected even by the most carefully spoken person of extreme moral sensibility.
We are indebted to modern physicians for the discovery of relations between word and brain. The physician has laid bare the only link ever found by science between mind and matter. It came about through the study of injuries to the human brain. The vivisection of brutes never could have revealed it. Thus it has been demonstrated that an injury to the visual-area of speech produces word-blindness. That is to say, the eyesight is unimpaired, but the portion of the brain that registers for interpretation the written or the printed word becomes illiterate and useless. Oral words are correctly registered in another area, and still another region of the brain permits them to be intelligently uttered.
Likewise a damage to the auditory locality of speech may produce total word-deafness whilst the victim still retains the perfect faculties of reading and writing. Such unfortunate persons may be deaf to words, as words, spoken either by themselves or others; and consequently they are capable only of incoherent speech while yet competent to recognize a multitude of other sounds as well and as rationally as ever.
Another kind of word-failure, or aphasia with agraphia resulting from brain injury, is common. The patient sees, hears, and understands the spoken or the written word, but he is incapable of speaking or writing it. That is to say, his motor-mechanism of speech is destroyed.
Three distinct speech-areas have been located in the brain, while a fourth exists which has not yet perhaps been found. We are conscious of words reaching us through the three special senses of sight, hearing, and touch. The visual-area is known to be in the cortex of the angular gyrus; the auditory-area is found in the first temporal convolution; the touch-area, developed in the deaf- and blind-mute, has not, I believe, been found. These are the passive or sensory areas of speech which register the incoming words. That part of the faculty of speech which is active is called the motor-center. This area contains the mechanism for giving forth words orally and in writing, as well as speech-signs and gestures. The center lies in another part of the brain cortex closely related to the areas which start the muscular movements of articulation; and it is contiguous to the region that governs the movements of the hands. This small body of gray matter is located, as we have seen, in the convolution of Broca. Every spoken and written word depends on the integrity of this little body which, when injured in adult life, renders it difficult for the will to utilize the corresponding body in the opposite hemisphere—after middle life it virtually is impossible.
These areas of the brain which harbor the faculty of speech do not originate our words any more than paper and type originate them; but like paper and type the sensory areas register the incoming words, and like a phonograph the motor-areas discharge the outgoing words. Therefore, of the mind all words are born; in the mind they dwell and have their being; but in the brain a mysterious mechanism gives them currency.
A curious characteristic of this mechanism—one that identifies it as a mechanism—is that it can not turn out indifferently the product of two languages. Each language requires its own anatomical area. The group of cells educated for English, for instance, can not be made to turn out another language. Each language must have its own group of cells. This has been demonstrated clinically in the study of injuries to the brains of polyglots. A man knowing several languages may have the area of one destroyed and retain the others. These areas are so intimately related, however, that harm done to the group of cells built up for one language is very likely to damage the other groups; although in the reports of Hinshelwood, of the University of Glasgow, it is recorded that a patient retained his Greek perfectly, his Latin less well, and that he was progressively weaker in French and English—the last being his mother-tongue; also that the progressive weakness of his power over the several tongues was in the reverse order of their respective acquirements. This anatomical characteristic, or mechanism, of the speech-areas seems to be general with them.
Another mystery of words in relation to their centers in the brain clings to this clinical fact: When the most usual form of aphasia, for example, is produced by disease, and when the disease yields to medical treatment, the patient recovers his verbs first and his nouns last. Clinical observation has noted that as recovery advances the verbs come first, later the prepositions, and last of all the nouns.
This is mentioned as one of the mysteries of words, and so it seems to be, although Dr. William Hanna Thomson, in his remarkable work on Brain and Personality, says: “The reasons for all this are that verbs are our innermost and, therefore, first learned words, because we know that we see, we hear, etc.; before we know what it is we see or hear, while nouns represent things outside of (?) us to which we lastly give names. The nouns which we learn after all others, and therefore forget soonest, are the names of persons, so that elderly people very commonly complain how (?) they can not recall persons’ names.”
Founded on some of the theories of memory, this is good reasoning; but it pushes back the mystery only a step. Why should this mechanism manifest a peculiar selective power over the different parts of speech? Why should the verb-cells be stronger than the noun-cells? Or if there be no actual verb-cells and noun-cells, why should the verb-impressions be deeper than the noun-impressions? Again, if they are not “impressions” but rather the functions of automatic cells fixed by habit, why should these functions wake up from the slumber of disease with a verb rather than a noun on their lips. After impairment, why should this gray matter resume its function with a selective affinity for verbs over the other parts of speech? There are nouns as old as verbs—perhaps older. Man probably named many things before he was conscious of their functions and qualities. The question may be solved when we learn more of our subconscious nature. This and many other mysteries of words may clear up as our knowledge increases of physiology and psychology; for, although we have made great progress in these studies, still we may be only in the primary grades.
Disturbances of the faculty of speech in brain-shock or paraphasia have been carefully studied; and it has been noted in this condition that while the patient may be able to speak, his words show a tendency to jumble. Wrong words persistently and vexatiously present themselves. That is to say, the mechanism in the region of Broca is out of order; it fails to function properly. If words originated in the mechanism and not in the ideas, of which the words are symbols, there would be no consciousness of faulty function—of the wrong word. But the contrary happens: the mind is conscious of the failure of its machine to do its work. This indicates that the mind makes use of this part of the brain at least, much as one uses a typewriting or other similar machine. In using a damaged typewriting machine, for instance, one may have a clear motive and he may be able to strike the keys accurately, but the instrument responds faultily with wrong letters (parts of words) just as a slightly injured speech-area responds to clear purpose with faulty words (parts of speech). If the mind were only a function of the brain—or at least, if words were a function of the speech-center, merely—naturally there would be no consciousness of impairment. This phase of consciousness, therefore, must occupy some complex in time or space or relationship outside, if not separate from, that occupied by the functions of the brain. All this deepens the mysteries surrounding our words; or, rather, as we think on the subject, we become more keenly aware of our lack of exact knowledge—certainly, in the relationship of brain to mind.
For the most part, the brain is a barren waste. Only a few parts of the cortex have been cultivated and made productive; yet there are many useful little garden patches which have been tilled by labor, titillated by play, and watered with tears besides the little areas of speech. There is one, not yet located I believe, which registers musical notes, and another to give them forth. These regions may remain uncultivated and lie fallow through life; or having been cultivated, they may be rendered useless and sterile by accident or disease while the speech-areas remain unharmed. There is a register-area for mathematics, another for form, and another for color. We all have known great artists! consummate colorists, exquisite delineators, and superb acrobatic performers on musical instruments who were virtual idiots otherwise almost entirely. The specialized mechanisms in the brain are, it is true, so related that damage done to one usually impairs others; but sometimes it does not. One exception is enough to kill any rule.
There also are well-developed regions in the gray matter for the registration and the giving forth of mathematical symbols expressing series, functions, etc., as well as arithmetical numbers. Dr. Thomson reports a case (Brain and Personality) of word-blindness and muteness caused by apoplexy. Yet the patient was capable of directing his extensive business affairs during the seven remaining years of his life; and he also was competent to make his will, because his auditory mechanism and his faculty of reading and writing figures were unharmed. He tried persistently to regain some of his lost power over words, and failed. Dr. Thomson says: “Mentally he was just the same, and his personality with all its peculiarities remained the same, but those particular chords of the instrument were irretrievably broken.”
What then were these “particular chords of the instrument,” and how do they relate words to mind? How is the mysterious link which has been discovered by the physician in the brain of man to be interpreted by the philosopher in the realm of thought? Until this interpretation is satisfactorily made, the mystery of words deepens.
To repeat! The structure of man’s brain and that of the anthropoid ape’s differ in no respect. The same anatomical features are present in both. Both have the convolutions in pairs. Each hemisphere, both in man and ape, duplicates the other. In man the speech-area is located in one hemisphere—in the ape, in neither. If speech depended solely on the anatomy of the brain, the highest tribe of apes should be as capable of speech as the lowest tribes of men. For the same reason the speech-area should be doubled; that is to say, it would be found in both hemispheres. But no speech-area exists in the brain of ape, and it occurs virtually in only one hemisphere of the brain of man. The other hemisphere of the human brain remains as barren as both hemispheres of the ape’s brain. The faculty of speech therefore did not originate in anatomy. Since it exists, its origin must have been .
In all right-handed persons, then, it is the left hemisphere of the brain that holds the speech-centers. Words are uttered by means of the left convolution of Broca; they are seen by means of the left angular gyrus; they are heard by means of the left superior temporal convolution. Where they are felt, by the right-handed blind deaf-mute, is not known precisely; but that this center also lies in the left hemisphere there is no doubt.
The bald fact that the left cerebral hemisphere has held the speech-centers of the majority of mankind through its long history would indicate that the left brain differed in some innate respect from its twin, the right. Such inference would be incorrect, however, because some persons, in no sense inferior to the others, have their speech-faculties as exclusively located in the right hemisphere as the large majority of folk have in the left, Therefore one must look elsewhere than in original structure, composition, relationship, etc., for the reason why the faculty of speech became localized in one side of the brain—usually the left.
Originally the brain is uniform of structure throughout in apelike man and manlike ape. No part of it is endowed with the faculty of speech. The mind of apelike man begins to feel the need of language. It is more and more pressed by necessity. The instrumentality of words becomes an imperious need at some epoch in time—at some phase of evolution—at some peak of change—on some plane of development—or at some state of consciousness. This need becomes a necessity in the early stages of human development. The birth of language now can not be delayed. Meanwhile the mind has been seeking methods and means of satisfying the want—of obeying the law. It would be futile to try to follow the methods understandingly or to try to describe them intelligently. It is possible, nevertheless, even with our lack of knowledge and poverty of data to take a glimpse at the means.
The first speech was gestural, and very largely gestural its successors remain. Primitive man struggled with gestural problems which he tried to bend to his Will. His will was to communicate with his fellows. Gesture was his most effective, if not only, means. He probably was right-handed then as his generations mostly have been since; but whether right- or left-handed, his hand was his chief organ of gesture. That part of his brain which governed the movements of his most effective gestural organ was the part that must have been most susceptible to the educational influences of his will. Thus the physiological intimacy began between hand and speech-center.
The area in the brain which controls the movements of the hand is closely associated with the area that governs the muscular movements of face, lips, and tongue. That there is a relationship between gesture and grimace may be readily demonstrated. Facial expression is known to be closely related to movements of lips and tongue. From gesture to grimace; from facial expression to guttural, lingual, and labial sound is only a step when largely considered. Of course the mind dominated gesture, grimace, and vocal sound; for without the human mind the sounds, and all the rest, must have remained like those of the ape—they never could have developed into human language.
Right-handed man naturally used his right-hand more than his left in his early sign-speech. As the will sought to assist the hand by forcing other organs to take part in speech, it adopted what one might well call a common-sense-method. The centers in the left brain most closely associated with the governing center of the right-hand were pressed into service. Obviously, it is more in harmony with the principle of common sense to call upon nearby associates in the left brain than to seek aid by crossing to the right over the bridge called corpus collosum. Hence the habit of doing this special work became fixed for life in the centers of the left brain.
What caused the general run of mankind to use one hand more than the other is unknown. The phenomenon may be related in some way to the law of rhythm that seems to operate throughout all nature. All that can be said about it is that nature makes it a rule to accent, as it were, one of a pair of organs. They never are exactly alike in size, shape, or intensity of function. That the right-hand should have received this “accent” or functional emphasis through the ages is another mystery associated with words through their relationship with hand and brain.
The reason why some persons are left-handed and fewer ambidexterous is not essential to the present discussion. It is sufficient to note that the speech-centers of the left-handed are situated in the right brain. The relationship between the hand and the mechanism of speech in the brain is conclusively established by the fact that the hand most used determines by force of habit to what part of the brain words must go for registration, and from what part they must come on their mission from mind to mind.
From known facts it is reasonable to assume that the ambidexterous person has speech-centers developed in both hemispheres of the brain. I am not aware that clinical experience has shown this to be true; but that it is true of the perfectly ambidexterous, there can be little doubt. If it is true, it presents an educational problem of importance to infancy and youth. For, by developing the speech-centers in both hemispheres the person would be considerably fortified against the possible aphasias in later life, caused by traumatism and disease.
It would be interesting, but not to the point, to compare the theories which try to elucidate the process by which the hand, for example, obeys its motor-center in the brain. The fact that it does obey that center is enough for present purposes.
The speech-center of Broca’s convolution, for instance, is of the brain itself. What then is the physiology of its function? Why is one of Broca’s convolutions dumb through life, and why does the other speak? To say that words are of automatic origin does not explain the function of speech. If it can be shown, however, that secondary anatomical changes are purposely, albeit subconsciously, wrought in certain areas of brain substance, then the mystery may be penetrated a little way farther.
The sounds of words may be imitated automatically and thus endlessly repeated; but they can not be used as words—as parts of speech—until they are defined or given meaning. The definitions of words must be learned. The learning of word-meanings is a process much more complicated than the act of repeating their sounds. The complexity is increased in learning to read, for there is no similarity between the sound of a spoken word and the appearance of one written.
From the vast amount of data available, it may be safely assumed that any normal person of any tribe can be taught to read. Learning to read is a laborious process: it requires acute attention, perseverance of application, and a long series of repetitions in order to identify the letters of a word, and to associate meanings with words separately and in their combinations. The word and its signification—the symbol and the idea—must be simultaneously recognized by the mind through alterations specially made in definite regions of brain substance. This only can be accomplished through duration in time by concentrated and specific effort. It would hardly do to call the process automatic. If any process may be imputed to the will, certainly this one may be. Besides, it easily is demonstrable that until some modification of gray matter is effected, the process of learning to read does not take place.
The principle underlying the mastery of a language is exemplified in the well-known reaction of nerve to a stimulus. Usually the nerve-substance is only slightly disturbed at first; that is to say, the reaction is feeble and brief; but a continual repetition of the stimulus increases the disturbance, intensifies the reaction until through habit, or what not, a permanent alteration is brought about in the nerve-substance. A new function follows the alteration; the function becomes more and more nearly constant under successive acts of stimulation.
It is only through the “spirit’s plastic stress” and a corresponding susceptibility of the gray matter that education conceivably is possible. Thus only may a part of the brain be taught a new function; and thus only may it be cultivated to receive and to bring forth that of which it previously was incapable. It is true that no physical changes have been observed in the gray matter cultivated by act of will often repeated; but if physical interference may disturb nervous function, it follows that physical changes have occurred in the substance during the process of its education.
If the brain-cells could teach themselves, there would be no conscious effort—no consciousness of will-power—in the learning of a language. There must be effort back of the stimulus to initiate it; and back of the effort there must be purpose; and back of all there must be will-power to stabilize and to make continuous the purpose in a series of intelligent efforts. The detached question of will, imagination, and personality, is quite another matter.
The proof that there are material changes in the cell-groups of gray matter which have been educated in language is shown, as we have seen, by the study of injuries to the brains of polyglots who successively acquired several tongues. When the speech-area which governs the mastery of the mother-tongue is injured, the areas cultivated for the other languages may perform their functions without appreciable embarrassment. This proves that there are definite and distinct regions in the nervous substance which have been modified: one for the requirements of one language, and one for those of another. Whether these modifications are wrought in strata or in superficial contiguous zones would be difficult to say. This however is sure: That which is subject to material interference must have some material basis.
So we see that the human brain, in regard to language with which we are now concerned, is capable of a vast increase of function not only, but also of the acquirement of new functions over those that came by inheritance.
The mysteries of words, then, when slightly penetrated or pushed backward, are seen to involve educational and ethical problems of importance. All training indeed, whether artistic, scientific, or moral, no longer can be regarded vaguely as “mental,” but must be recognized as involving physical changes in nervous substance; and that only through the modification of nervous substance may any training produce permanent or practical results.
No doubt, all the arts and crafts have their special centers in the cortex of the brain. In learning the art of painting, for example, it is as necessary to modify some part of the brain-substance as it is in the process of acquiring a language. The same principle applies to all the handicrafts, as has been proved repeatedly by clinical experience.