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. To follow farther the influence that the use of speech as a means of understanding has upon the intellectual development of the child lies outside the problem dealt with in this book. Let me, in conclusion, simply give a brief estimate of the questioning-activity that makes its appearance very early after the first attempts at speech, and also add a few remarks on the development of the _"I"-feeling_.