mpound "friction-sounds" (fl, schl). But it is only in part
that the surroundings determine this order of succession for the sounds.
Another thing that partly determines and modifies this order is the
child's own unwearied practice in forming consonant-sounds. He hears his
own voice now better than he did at an earlier period when he was
forming vowels only. He most easily retains and repeats, among the
infinitely manifold consonants that are produced by loud expiration,
those which have been distinctly heard by him. This is owing to the
association of the motor and the acoustic memory-image in the brain.
These are the most frequent in his speech. Not until later does the
mechanical difficulty of articulation exert an influence, and this comes
in at the learning of the compound sounds. Hence there can not be any
chronological order of succession of sounds that holds good universally
in the language of the child, because each language has a different
order in regard to the frequency of appearance of the sounds; but
heredity can have no influence here, because every child of average
gifts, though it may hear from its birth a language unknown to its
ancestors, if it hears no other, yet learns to speak this language
perfectly. What is hereditary is the great plasticity of the entire
apparatus of speech, the voice, and with it a number of sounds that are
not acquired, as _m_. An essential reason for the defective formation of
sounds in children born deaf is the fact that they do not hear their own
voice. This defect may also be hereditary.

The treatise of F. Schultze contains, besides, many good remarks upon
the _technique_ of the language of the child, but, as they are of
inferior psychogenetic interest, they need not be particularly mentioned
here. Others of them are only partially confirmed by the observations,
as is shown by a comparison with what follows.

Gustav Lindner ("Twelfth Annual Report of the Lehrer-seminars at
Zschopau," 1882, p. 13) heard from his daughter, in her ninth week,
_arra_ or _aerrae_, which was uttered for months. Also _aeckn_ appeared
early. The principle of the least effort Lindner finds to be almost
absolutely refuted by his observations. He rightly remarks that the
frequent repetitions of the same groups of sounds, in the babbling
monologues, are due in part to a kind of pleasure in success, such as
urges adults also to repeat their successful efforts. Thus his child
used to imitate the readi