No doubt this behavior varies in individual cases, inasmuch as in some few the imitative articulation may be to some extent earlier developed than the understanding. There are many children who even in their first year have a monkey-like knack at imitation and repeat all sorts of things like parrots without guessing the sense of them. Here, however, it is to be borne in mind that such an echo-speech appears only after the first understanding of some spoken word can be demonstrated; in no case before the fourth month. Lindner relates that when he one day observed that his child of eighteen weeks was gazing at the swinging pendulum of the house-clock, he went with him to it, saying, "Tick-tack," in time with the pendulum; and when he afterward called out to the child, who was no longer looking at the clock, "Tick-tack!" this call was answered, at first with delay, a little later immediately, by a turning of the look toward the clock. This proved that there was understanding long before the first imitation of words. Progress now became pretty rapid, so that at the end of the seventh month the questions, "Where is your eye? ear? head? mouth? nose? the table? chair? sofa?" were answered correctly by movements of hand and eyes. In the tenth month this child for the first time himself used a word as a means of effecting an understanding, viz., mama (soon afterward, indeed, he called both parents papa). The child's inability to repeat distinctly syllables spoken for him is not to be attributed, shortly before the time at which he succeeds in doing it, to a purely psychical adynamy (impotence), not, as many suppose, to "being stupid," or to a weakness of will without organic imperfections determined by the cerebral development, for the efforts, the attention, and the ability to repeat incorrectly, show that the will is not wanting. Since also the peripheral impressive acoustic and expressive phonetic paths are intact and developed, as is proved by the acuteness of the hearing and the spontaneous formation of the very syllables desired, the cause of the inability to repeat correctly must be solely organic-centro-motor. The connecting paths between the sound-center and the syllable-center, and of both these with the speech motorium, are not yet or not easily passable; but the imitation of a single sound, be it only a, can not take place without the mediation of the cerebral cortex. Thus in the very first attempt to repeat something heard there exists an unquestionable advance in brain development; and the first successful attempt of this kind proves not merely the augmented functional ability of the articulatory apparatus and of the sound-center, and the practicability of the impressive paths that lead from the ear to the sound-center—it proves, above all, the establishment of intercentral routes that lead from the sound-center and the syllable-center to the motorium.
In fact, the correct repeating of a sound heard, of a syllable, and, finally, of a word pronounced by another person, is the surest proof of the establishment and practicability of the entire impressive, central, and expressive path. It, however, proves nothing as to the understanding of the sound or word heard and faultlessly repeated.
As the term "understanding" or "understand" is ambiguous, in so far as it may relate to the ideal content (the meaning), and at the same time to the mere perception of the word spoken (or written or touched)—e. g., when any one speaks indistinctly so that we do not "understand" him—it is advisable to restrict the use of this expression. Understand shall in future apply only to the meaning of the word; hear—since it is simply the perceiving of a word through the hearing that we have in view—will relate to the sensuous impression. It is clear, then, that all children who can hear but can not yet speak, repeat many words without understanding them, and understand many words without being able to repeat them, as Kussmaul has already observed. But I must add that the repeating of what is not understood begins only after some word (even one that can not be repeated) has been understood.
Now it is certain that the majority, if not all, of the children that have good hearing develop the understanding more at first, since the impressive side is practiced more and sooner than the expressive-articulatory. Probably those that imitate early and skillfully are the children that can speak earliest, and whose cerebrum grows fastest but also soonest ceases to grow; whereas those that imitate later and more sparingly, generally learn to speak later, and will generally be the more intelligent. For with the higher sort of activity goes the greater growth of brain. While the other children cultivate more the centro-motor portion, the sensory, the intellectual, is neglected. In animals, likewise, a brief, rapid development of the brain is wont to go along with inferior intelligence. The intelligence gets a better development when the child, instead of repeating all sorts of things without any meaning, tries to guess the meaning of what he hears. Precisely the epoch at which this takes place belongs to the most interesting in intellectual development. Like a pantomimist, the child, by means of his looks and gestures, and further by cries and by movements of all sorts, gives abundant evidence of his understanding and his desires, without himself speaking a single word. As the adult, after having half learned a foreign language from books, can not speak (imitate) it, and can not easily understand it when he hears it spoken fluently by one that is a perfect master of it, but yet makes out single expressions and understands them, and divines the meaning of the whole, so the child at this stage can distinctly hear single words, can grasp the purport of them, and divine correctly a whole sentence from the looks and gestures of the speaker, although the child himself makes audible no articulate utterance except his own, for the most part meaningless, variable babble of sounds and syllables and outcries.
The causes of the slowness of the progress in expressing in articulate words what is understood and desired, on the part of normal children, is not, however, to be attributed, as it has often been, to a slower development of the expressive motor mechanism, but must be looked for in the difficulty of establishing the connection of the various central storehouses of sense-impressions with the intercentral path of connection between the acoustic speech-centers and the speech-motorium. For the purely peripheral articulatory acts are long since perfect, although as yet a simple "a" or "pa" can not be repeated after another person; for these and other sounds and syllables are already uttered correctly by the child himself.
The order of succession in which these separate sounds appear, without instruction, is very different in individual cases. With my boy, who learned to speak rather late, and was not occupied with learning by heart, the following was the order of the perfectly pure sounds heard by me:
On the left are the sounds or syllables indicated by one letter; on the right, the same indicated by more than one letter; and it is to be borne in mind that the child needs to pronounce only fourteen of the nineteen so-called consonants of the German alphabet in order to master the remaining five also; for
| c = ts and k |
| v = f and w |
| x = ks and gs |
| q = ku and kw |
| z = ts and ds |
and of the fourteen four require no new articulation, because
| p is a toneless b |
| t is a toneless d |
| f is a toneless w |
| k is a toneless g |