Chapter I: Preface

The contents of this little book formed the subject of three lectures delivered at the Royal Institution "On the Mechanism of the Human Voice" and three London University lectures at King's College on "The Brain in relation to Speech and Song." I have endeavoured to place this subject before my readers in as simple language as scientific accuracy and requirements permit. Where I have been obliged to use technical anatomical and physiological terms I have either explained their meaning in the text, aided by diagrams and figures, or I have given in brackets the English equivalents of the terms used.

I trust my attempt to give a sketch of the mechanism of the human voice, and how it is produced in speech and song, may prove of interest to the general public, and I even hope that teachers of voice production may find some of the pages dealing with the brain mechanism not unworthy of their attention.

F.W. MOTT

LONDON

_July, 1910_

CONTENTS

THEORIES ON THE ORIGIN OF SPEECH

THE VOCAL INSTRUMENT: THREE QUALITIES OF MUSICAL SOUNDS, LOUDNESS, PITCH AND TIMBRE

THE VOCAL INSTRUMENT AND ITS THREE PARTS

(1) THE BELLOWS AND ITS STRUCTURE: VOLUNTARY CONTROL OF BREATH

(2) THE REED CONTAINED IN THE VOICE-BOX OR LARYNX: ITS STRUCTURE AND ACTION

(3) THE RESONATOR AND ARTICULATOR, ITS STRUCTURE AND ACTION IN SONG AND SPEECH

PATHOLOGICAL DEGENERATIVE CHANGES PRODUCING SPEECH DEFECTS AND WHAT THEY TEACH

THE CEREBRAL MECHANISM OF SPEECH AND SONG

SPEECH AND RIGHT-HANDEDNESS

LOCALISATION OF SPEECH CENTRES IN THE BRAIN

THE PRIMARY SITE OF REVIVAL OF WORDS IN SILENT THOUGHT

CASE OF DEAFNESS ARISING FROM DESTRUCTION OF THE AUDITORY CENTRES IN THE BRAIN CAUSING LOSS OF SPEECH

THE PRIMARY REVIVAL OF SOME SENSATIONS IN THE BRAIN

PSYCHIC MECHANISM OF THE VOICE

ILLUSTRATIONS

FIG.

1. The thoracic cage and its contents

2. The diaphragm and its attachments

3. Diagram illustrating changes of the chest and abdomen in breathing

4. Diagram of the cartilages of the voice-box or larynx with vocal cords

5. Front view of the larynx with muscles

6. Back view of the larynx with muscles

7. Diagram to illustrate movements of cartilages in breathing and phonation

8. Section through larynx and windpipe, showing muscles and vocal cords

9. The laryngoscope and its use

10. The glottis in breathing, whispering, and vocalisation

11. The vocal cords in singing, after French

12. Vertical section through the head and neck to show the larynx and resonator

13. Diagram (after Aikin) of the resonator in the production of the vowel sounds

14. König's flame manometer

15. Diagram of a neurone

16. Left hemisphere, showing cerebral localisation

17. Diagram to illustrate cerebral mechanism of speech, after Bastian

18. The course of innervation currents in phonation

THE BRAIN AND THE VOICE IN SPEECH AND SONG

In the following pages on the Relation of the Brain to the mechanism of the Voice in Speech and Song, I intend, as far as possible, to explain the mechanism of the instrument, and what I know regarding the cerebral mechanism by which the instrument is played upon in the production of the singing voice and articulate speech. Before, however, passing to consider in detail the instrument, I will briefly direct your attention to some facts and theories regarding the origin of speech.

THEORIES ON THE ORIGIN OF SPEECH

The evolutionary theory is thus propounded by Romanes in his "Mental Evolution in Man," pp. 377-399: "Starting from the highly intelligent and social species of anthropoid ape as pictured by Darwin, we can imagine that this animal was accustomed to use its voice freely for the expression of the emotions, uttering danger signals, and singing. Possibly it may also have been sufficiently intelligent to use a few imitative sounds; and certainly sooner or later the receptual life of this social animal must have advanced far enough to have become comparable with that of an infant of about two years of age. That is to say, this animal, although not yet having begun to use articulate signs, must have advanced far enough in the conventional use of natural signs (a sign with a natural origin in tone and gesture, whether spontaneously or intentionally imitative) to have admitted of a totally free exchange of receptual ideas, such as would be concerned in animal wants and even, perhaps, in the simplest forms of co-operative action. Next I think it probable that the advance of receptual intelligence which would have been occasioned by this advance in sign-making would in turn have led to a development of the latter--the two thus acting and reacting on each other until the language of tone and gesture became gradually raised to the level of imperfect pantomime, as in children before they begin to use words. At this stage, however, or even before it, I think very probably vowel sounds must have been employed in tone language, if not also a few consonants. Eventually the action and reaction of receptual intelligence and conventional sign-making must have ended in so far developing the former as to have admitted of the breaking up (or articulation) of vocal sounds, as the only direction in which any improvement in vocal sign-making was possible." Romanes continues his sketch by referring to the probability that this important stage in the development of speech was greatly assisted by the already existing habit of articulating musical notes, supposing our progenitors to have resembled the gibbons or the chimpanzees in this respect. Darwin in his great work on the "Expression of the Emotions" points to the fact that the gibbon, the most erect and active of the anthropoid apes, is able to sing an octave in half-tones, and it is interesting to note that Dubois considers his Pithecanthropus Erectus is on the same stem as the gibbon. But it has lately been shown that some animals much lower in the scale than monkeys, namely, rodents, are able to produce correct musical tones. Therefore the argument loses force that the progenitors of man probably uttered musical sounds before they had acquired the power of articulate speech, and that consequently, when the voice is used under any strong emotion, it tends to assume through the principle of association a musical character. The work of anthropologists and linguists, especially the former, supports the progressive-evolution theory, which, briefly stated, is--that articulate language is the result of an elaboration in the long procession of ages in which there occurred three stages--the cry, vocalisation, and articulation. The cry is the primordial, pure animal language; it is a simple vocal aspiration without articulation; it is either a reflex expressing needs and emotions, or at a higher stage intentional (to call, warn, menace, etc.). Vocalisation (emission of vowels) is a natural production of the vocal instrument, and does not in itself contain the essential elements of speech. Many animals are capable of vocalisation, and in the child the utterance of vowel sounds is the next stage after the cry.

The conditions necessary to the existence of speech arose with articulation, and it is intelligence that has converted the vocal instrument into the speaking instrument. For whereas correct intonation depends upon the innate musical ear, which is able to control and regulate the tensions of the minute muscles acting upon the vocal cords, it is intelligence which alters and changes the form of the resonator by means of movement of the lips, tongue, and jaw in the production of articulate speech. The simple musical instrument in the production of phonation is bilaterally represented in the brain, but as a speaking instrument it is unilaterally represented in right-handed individuals in the left hemisphere and in left-handed individuals in the right hemisphere. The reason for this we shall consider later; but the fact supports Darwin's hypothesis.

Another hypothesis which was brought forward by Grieger and supported by some authors is summarised by Ribot as follows: "Words are an imitation of the movements of the mouth. The predominant sense in man is that of sight; man is pre-eminently visual. Prior to the acquisition of speech he communicated with his fellows by the aid of gestures and movement of the mouth and face; he appealed to their eyes. Their facial 'grimaces,' fulfilled and elucidated by gesture, became signs for others; they fixed their attention upon them. When articulate sounds came into being, these lent themselves to a more or less conventional language by reason of their acquired importance." For support of this hypothesis the case of non-educated deaf-mutes is cited. They invent articulate sounds which they cannot hear and use them to designate certain things. Moreover, they employ gesture language--a language which is universally understood.

Another theory of the origin of the speaking voice is that speech is an instinct not evolved, but breaking forth spontaneously in man; but even if this be so, it was originally so inadequate and weak that it required support from the gesture language to become intelligible. This mixed language still survives among some of the inferior races of men. Miss Kingsley and Tylor have pointed out that tribes in Africa have to gather round the camp fires at night in order to converse, because their vocabulary is so incomplete that without being reinforced by gesture and pantomime they would be unable to communicate with one another. Gesture is indispensable for giving precision to vocal sounds in many languages, e.g. those of the Tasmanians, Greenlanders, savage tribes of Brazil, and Grebos of Western Africa. In other cases speech is associated with inarticulate sounds. These sounds have been compared to clicking and clapping, and according to Sayce, these clickings and clappings survive as though to show us how man when deprived of speech can fix and transmit his thoughts by certain sounds. These mixed states represent articulate speech in its primordial state; they represent the stage of transition from pure pantomime to articulate speech.

It seems, then, that originally man had two languages at his disposal which he used simultaneously or interchangeably. They supported each other in the intercommunication of ideas, but speech has triumphed because of its greater practical utility. The language of gesture is disadvantageous for the following reasons: (1) it monopolises the use of the hands; (2) it has the disadvantage that it does not carry any distance; (3) it is useless in the dark; (4) it is vague in character; (5) it is imitative in nature and permits only of the intercommunication of ideas based upon concrete images. Speech, on the other hand, is transmitted in the dark and with objects intervening; moreover, distance affects its transmission much less. The images of auditory and visual symbols in the growth of speech replace in our minds concrete images and they permit of abstract thought. It is dependent primarily upon the ear, an organ of exquisite feeling, whose sensations are infinite in number and in kind. This sensory receptor with its cerebral perceptor has in the long process of time, aided by vision, under the influence of natural laws of the survival of the fittest, educated and developed an instrument of simple construction (primarily adapted only for the vegetative functions of life and simple vocalisation) into that wonderful instrument the human voice; but by that development, borrowing the words of Huxley, "man has slowly accumulated and organised the experience which is almost wholly lost with the cessation of every individual life in other animals; so that now he stands raised as upon a mountain-top, far above the level of his humble fellows, and transfigured from his grosser nature by reflecting here and there a ray from the infinite source of truth." Thought in all the higher mental processes could not be carried on at all without the aid of language.

Written language probably originated in an analytical process analogous to the language of gesture. Like that, it: (1) isolates terms; (2) arranges them in a certain order; (3) translates thoughts in a crude and somewhat vague form. A curious example of this may be found in Max Müller's "Chips from a German Workshop," XIV.: "The aborigines of the Caroline Islands sent a letter to a Spanish captain as follows: A man with extended arms, sign of greeting; below to the left, the objects they have to barter--five big shells, seven little ones, three others of different forms; to the right, drawing of the objects they wanted in exchange--three large fish-hooks, four small ones, two axes, two pieces of iron."

Language of graphic signs and spoken language have progressed together, and simultaneously supported each other in the development of the higher mental faculties that differentiate the savage from the brute and the civilised human being from the savage. In spoken language, at any rate, it is not the vocal instrument that has been changed, but the organ of mind with its innate and invisible molecular potentialities, the result of racial and ancestral experiences in past ages. Completely developed languages when studied from the point of view of their evolution are stamped with the print of an unconscious labour that has been fashioning them for centuries. A little consideration and reflection upon words which have been coined in our own time shows that language offers an abstract and brief chronicle of social psychology.

Articulate language has converted the vocal instrument into the chief agent of the will, but the brain in the process of time has developed by the movements of the lips, tongue, jaw, and soft palate a kinæsthetic[A] sense of articulate speech, which has been integrated and associated in the mind with rhythmical modulated sounds conveyed to the brain by the auditory nerves. There has thus been a reciprocal simultaneity in the development of these two senses by which the mental ideas of spoken words are memorised and recalled. Had man been limited to articulate speech he could not have made the immense progress he has made in the development of complex mental processes, for language, by using written verbal symbols, has allowed, not merely the transmission of thought from one individual to another, but the thoughts of the world, past and present, are in a certain measure at the disposal of every individual. With this introduction to the subject I will pass on to give a detailed description of the instrument of the voice.

[Footnote A: Sense of movement.]

THE VOCAL INSTRUMENT

A distinction is generally made in physics between sound and noise. Noise affects our tympanic membrane as an irregular succession of shocks and we are conscious of a jarring of the auditory apparatus; whereas a musical sound is smooth and pleasant because the tympanic membrane is thrown into successive periodic vibrations to which the auditory receptor (sense organ of hearing) has been attuned. To produce musical sounds, a body must vibrate with the regularity of a pendulum, but it must be capable of imparting sharper or quicker shocks to the air than the pendulum. All musical sounds, however they are produced and by whatever means they are propagated, may be distinguished by three different qualities:

(1) Loudness, (2) Pitch, (3) Quality, timbre or klang, as the Germans call it.

Loudness depends upon the amount of energy expended in producing the sound. If I rub a tuning-fork with a well-rosined bow, I set it in vibration by the resistance offered to the rosined hair; and if while it is vibrating I again apply the bow, thus expending more energy, the note produced is louder. Repeating the action several times, the width of excursion of the prongs of the tuning-fork is increased. This I can demonstrate, not merely by the loudness of the sound which can be heard, but by sight; for if a small mirror be fixed on one of the prongs and a beam of light be cast upon the mirror, the light being again reflected on to the screen, you will see the spot of light dance up and down, and the more energetically the tuning-fork is bowed the greater is the amplitude of the oscillation of the spot of light. The duration of the time occupied is the same in traversing a longer as in traversing a shorter space, as is the case of the swinging pendulum. The vibrating prongs of the tuning-fork throw the air into vibrations which are conveyed to the ear and produce the sensation of sound. The duration of time occupied in the vibrations of the tuning-fork is therefore independent of the space passed over. The greater or less energy expended does not influence the duration of time occupied by the vibration; it only influences the amplitude of the vibration.

The second quality of musical sounds is the pitch, and the pitch depends upon the number of vibrations that a sounding body makes in each second of time. The most unmusical ear can distinguish a high note from a low one, even when the interval is not great. Low notes are characterised by a relatively small number of vibrations, and as the pitch rises so the number of vibrations increase. This can be proved in many ways. Take, for example, two tuning-forks of different size: the shorter produces a considerably higher pitched note than the longer one. If a mirror be attached to one of the prongs of each fork, and a beam of light be cast upon each mirror successively and then reflected in a revolving mirror, the oscillating spot of light is converted into a series of waves; and if the waves obtained by reflecting the light from the mirror of the smaller one be counted and compared with those reflected from the mirror attached to the larger fork, it will be found that the number of waves reflected from the smaller fork is proportionally to the difference in the pitch more numerous than the waves reflected from the larger. The air is thrown into corresponding periodic vibrations according to the rate of vibration of the sound-producing body.

Thirdly, the quality, timbre, or klang depends upon the overtones, in respect to which I could cite many experiments to prove that whenever a body vibrates, other bodies near it may be set in vibration, but only on condition that such bodies shall be capable themselves of producing the same note. A number of different forms of resonators can be used to illustrate this law; a law indeed which is of the greatest importance in connection with the mechanism of the human voice. Although notes are of the same loudness and pitch when played on different instruments or spoken or sung by different individuals, yet even a person with no ear for music can easily detect a difference in the quality of the sound and is able to recognise the nature of the instrument or the timbre of the voice. This difference in the timbre is due to harmonics or overtones. Could we but see the sonorous waves in the air during the transmission of the sound of a voice, we should see stamped on it the conditions of motion upon which its characteristic qualities depended; which is due to the fact that every vocal sound whose vibrations have a complex form can be decomposed into a series of simple notes all belonging to the harmonic series. These harmonics or overtones will be considered later when dealing with the timbre or quality of the human voice.

The vocal instrument is unlike any other musical instrument; it most nearly approaches a reed instrument. The clarionet and the oboe are examples of reed instruments, in which the reed does not alter but by means of stops the length of the column of air in the resonating pipe varies and determines the pitch of the fundamental note. The organ-pipe with the vibrating tongue of metal serving as the reed is perhaps the nearest approach to the vocal organ; but here again it is the length of the pipe which determines the pitch of the note.

The vocal instrument may be said to consist of three parts: (1) the bellows; (2) the membranous reed contained in the larynx, which by the actions of groups of muscles can be altered in tension and thus variation in pitch determined; (3) the resonator, which consists of the mouth, the throat, the larynx, the nose, and air sinuses contained in the bones of the skull, also the windpipe, the bronchial tubes, and the lungs. The main and important part of the resonator, however, is situated above the glottis (the opening between the vocal cords, _vide_ fig. 6), and it is capable of only slight variations in length and of many and important variations in form. In the production of musical sounds its chief influence is upon the quality of the overtones and therefore upon the timbre of the voice; moreover, the movable structures of the resonator, the lower jaw, the lips, the tongue, the soft palate, can, by changing the form of the resonator, not only impress upon the sound waves particular overtones as they issue from the mouth, but simultaneously can effect the combination of vowels and consonants with the formation of syllables, the combination of syllables with the formation of words, and the combination of words with the formation of articulate language. The reed portion of the instrument acting alone can only express emotional feeling; the resonator, the effector of articulate speech, is the instrument of intelligence, will, and feeling. It must not, however, be thought that the vocal instrument consists of two separately usable parts, for phonation (except in the whispered voice) always accompanies articulation.

In speech, and more especially in singing, there is an art of breathing. Ordinary inspiration and expiration necessary for the oxygenation of the blood is performed automatically and unconsciously. But in singing the respiratory apparatus is used like the bellows of a musical instrument, and it is controlled and directed by the will; the art of breathing properly is fundamental for the proper production of the singing voice and the speaking voice of the orator. It is necessary always to maintain in the lungs, which act as the bellows, a sufficient reserve of air to finish a phrase; therefore when the opportunity arises it is desirable to take in as much air as possible through the nostrils, and without any apparent effort; the expenditure of the air in the lungs must be controlled and regulated by the power of the will in such a manner as to produce efficiency in loudness with economy of expenditure. It must be remembered, moreover, that mere loudness of sound does not necessarily imply carrying power of the voice, either when speaking or singing. Carrying power, as we shall see later, depends as much upon the proper use of the resonator as upon the force of expulsion of the air by the bellows. Again, a soft note, especially an aspirate, owing to the vocal chink being widely opened, may be the cause of an expenditure of a larger amount of air than a loud-sounding note. Observations upon anencephalous monsters (infants born without the great brain) show that breathing and crying can occur without the cerebral hemispheres; moreover, Goltz's dog, in which all the brain had been removed except the stem and base, was able to bark, growl, and snarl, indicating that the primitive function of the vocal instrument can be performed by the lower centres of the brain situated in the medulla oblongata. But the animal growled and barked when the attendant, who fed it daily, approached to give it food, which was a clear indication that the bark and growl had lost both its affective and cognitive significance; it was, indeed, a purely automatic reflex action. It was dependent upon a stimulus arousing an excitation in an instinctive automatic nervous mechanism in the medulla oblongata and spinal cord presiding over synergic groups of muscles habitually brought into action for this simplest form of vocalisation, connected with the primitive emotion of anger.

I will now consider at greater length each part of the vocal instrument.