Very young infants do not understand what is spoken, for the reason that they do not yet hear distinctly; o and a are still difficult for the acoustic nerve-excitement to traverse. Little children very easily hear wrong on this account.
B. The Central Processes Disturbed.
Dysphasia.—In the child that can use only a small number of words, the cerebral and psychical act through which he connects these with his ideas and gives them grammatical form and syntactical construction in order to express the movement of his thought is not yet complete.
(1) The Sensory Processes centrally disturbed.
Sensory Aphasia (Wernicke), Word-Deafness (Kussmaul).—The child, in spite of good hearing and sufficiently developed intelligence, can not yet understand spoken words because the path m is not yet formed and the storehouse of word images W is still empty or is just in the stage of origination.
Amnesia, Amnesic Dysphasia and Aphasia, Partial and Total Word-Amnesia, Memory-Aphasia.—The child has as yet no word-memory, or only a weak one, utters meaningless sounds and sound-combinations. He can not yet use words because he does not yet have them at his disposal as acoustic sound-combinations. In this stage, however, much that is said to him can be repeated correctly in case W is passable, though empty or imperfectly developed.
(2) The Sensori-motor Processes of Diction disturbed.
Acataphasia (Steinthal).—The child that has already a considerable number of words at his disposal is not yet in condition to arrange them in a sentence syntactically. He can not yet frame correct sentences to express the movement of his thought, because his diction-center D is still imperfectly developed. He expresses a whole sentence by a word; e. g., hot! means as much as "The milk is too hot for me to drink," and then again it may mean "The stove is too hot!" Man! means "A strange man has come!"
Dysgrammatism (Kussmaul) and Agrammatism (Steinthal).—Children can not yet put words into correct grammatical form, decline, or conjugate. They like to use the indefinite noun-substantive and the infinitive, likewise to some extent the past participle. They prefer the weak inflection, ignore and confound the articles, conjunctions, auxiliaries, prepositions, and pronouns. In place of "I" they say their own names, also tint (for "Kind"—child or "baby"). Instead of "Du, er, Sie" (thou, he, you), they use proper names, or man, papa, mamma. Sometimes, too, the adjectives are placed after the nouns, and the meaning of words is indicated by their position with reference to others, by the intonation, by looks and gestures. Agrammatism in child-language always appears in company with acataphasia, often also in insane persons. When the imbecile Tony says, "Tony flowers taken, attendant come, Tony whipped" (Tony Blumen genommen, Wärterin gekommen, Tony gehaut), she speaks exactly like a child (Kussmaul), without articles, pronouns, or auxiliary verbs, and, like the child, uses the weak inflection. The connection m of the word-image-center W with the diction-center D, i. e., of the word-memory with grammar, and the centers themselves, are as yet very imperfectly developed, unused.
Bradyphasia.—Children that can already frame sentences take a surprising amount of time in speaking on account of the slowness of their diction. In D and W m in the cerebral cortex the hindrances are still great because of too slight practice.