The greatest intellectual advance in this field consists in this, that the specific method of the human race is discovered by the speechless child—the method of expressing ideas aloud and articulately, i. e., by means of expirations of breath along with various positions of the larynx and the mouth and various movements of the tongue. No child invents this method, it is transmitted; but each individual child discovers that by means of sounds thus originating one can make known his ideas and thereby induce feelings of pleasure and do away with discomfort. Therefore he applies himself to this process of himself, without instruction, provided only that he grows up among speaking people; and even where hearing, which serves as a means of intercourse with them, is wanting from birth, a life rich in ideas and an intelligence of a high order may be developed, provided that written signs of sound supply the place of sounds heard. These signs, however, can be learned only by means of instruction. The way in which writing is learned is the same as the way in which the alalic child learns to speak. Both rest upon imitation.
I have shown that the first firm association of an idea with a syllable or with a word-like combination of syllables, takes place exclusively through imitation; but a union of this sort being once established, the child then freely invents new combinations, although to a much more limited extent than is commonly assumed. No one brings with him into the world a genius of such quality that it would be capable of inventing articulate speech. It is difficult enough to comprehend that imitation suffices for the child to learn a language.
What organic conditions are required for the imitation of sounds and for learning to speak I have endeavored to ascertain by means of a systematic collection, resting on the best pathological investigations, of all the disturbances of speech thus far observed in adults; and the daily observation of a sound child, who was kept away from all training as far as possible, as well as the frequent observation of other children, has brought me to the following important result:
That every known form of disturbance of speech in adults finds its perfect counterpart in the child that is learning to speak.
The child can not yet speak correctly, because his impressive, central, and expressive organs of speech are not yet completely developed. The adult patient can no longer speak correctly, because those parts are no longer complete or capable of performing their functions. The parallelism is perfect even to individual cases, if children of various ages are carefully observed in regard to their acquirement of speech. As to facts of a more general nature, we arrive, then, at the three following:
1. The normal infant understands spoken language much earlier than he can himself produce through imitation the sounds, syllables, and words he hears.
2. The normal child, however, before he begins to speak or to imitate correctly the sounds of language, forms of his own accord all or nearly all the sounds that occur in his future speech and very many others besides, and delights in doing it.
3. The order of succession in which the sounds of speech are produced by the infant is different with different individuals, and consequently is not determined by the principle of the least effort. It is dependent upon several factors—brain, teeth, size of the tongue, acuteness of hearing, motility, and others. Only in the later, intentional, sound-formations and attempts at speaking does that principle come under consideration.
In the acquirement of every complicated muscular movement, dancing, e. g., the difficult combinations which make a greater strain on the activity of the will are in like manner acquired last.
Heredity plays no part in this, for every child can learn to master perfectly any language, provided he hears from birth only the one to be learned. The plasticity of the inborn organs of speech is thus in the earliest childhood very great.