It also occurs--seldom, however--that children who have already learned to speak pretty well are dumb, or speak only a few words--among these the word _no_--during several months, or speak only with certain persons, because they _will not_ speak (out of obstinacy, or embarrassment). Here an organic obstacle in the motor speech-center is probable. For voluntary dumbness requires great strength of will, which is hardly to be attributed to the child. The unwillingness to speak that is prompted by _fun_ never lasts long. C. THE EXPRESSIVE PERIPHERAL PROCESSES DISTURBED. (1) Dyslalia and Alalia (Peripheral Dysarthria and Anarthria). The infant can _not yet_ articulate correctly, or at all, on account of the still deficient development, and afterward the lack of control, of the nerves of speech and the external organs of speech. The complete inability to articulate is called alalia. The newly born is alalic. Dyslalia continues with many children a long time even after the learning of the mother-tongue. This is always a case simply of imperfections in _h_ and _z_. _a. Bulbo-nuclear Stammering (Literal Bulbo-nuclear Dysarthria and Anarthria)._--Patients who have lost control over the muscles of speech through bulbo-nuclear paralysis, stammer before they become speechless, and along with paralysis and atrophy of the tongue occur regularly fibrillar contractions of the muscles of the tongue. The tongue is _no longer_ regulated by the will. The child that has not yet gained control over his vocal muscles stammers before he can speak correctly, and, according to my observations, regularly shows fibrillar contractions of the muscles of the tongue along with an extraordinary mobility of the tongue. The tongue is _not yet_ regulated by the will. Its movements are aimless. _b. Mogilalia._--Children, on account of the as yet deficient control of the external organs of speech, especially of the tongue, can _not yet_ form some sounds, and therefore omit them. They say, e. g., _in_ for "hin," _aetz_ for "Herz," _eitun_ for "Zeitung," _ere_ for "Schere." _Gammacism._--Children find difficulties in the voluntary utterance of K and Ks (_x_), and indeed of G, and therefore often omit these sounds without substituting others; they say, e. g., _atsen_ for "Klatschen," _atten_ for "Garten," _asse_ for "Gasse," _all_ for "Karl," _ete_ for "Grete" (in the second year), _wesen_ for "gewesen," _opf_ for "Kopf."