O'Shea—The Child's Linguistic Development. 181 
Romanes, 1 2 3 Whitney/ Sayce,® Muller, 4 Powell, 5 Brinton, 6 Bosan- 
quet, 7 and other students of primitive languages have pointed 
out, get along with single-word sentences. It seems to be well 
established that linguistic evolution on the phylogenetic side has 
proceeded by continual differentiation of the primitive sen¬ 
tence this differentiation resulting in our parts of speech 
and in their varied infected forms. So the infant’s expres¬ 
sion, on the verbal side, is a highly undifferentiated one; and 
the process of development consists, for one thing, in con¬ 
tinuous differentiation with specialization of function,—just such 
a process in principle as we see illustrated in the evolution of 
language in the race. 8 This method of development—continual 
differentiation with specialization of function—has universal 
validity in mental ontogeny, holding as well for linguistic as for 
other activities. 
It is apparent why, classifying the child’s vocabulary ah extra, 
we find that three-fifths of his words are nouns, the names of 
things, as Mrs. Moore, 9 Mrs. Hall, 10 Kirkpatrick 11 and others 
maintain. It is easy to overlook the pronominal, verbal, adjec¬ 
tival, adverbial, prepositional, and conjunctional function of the 
first words; as I have intimated, we unconsciously infer this func¬ 
tion from the child’s attitudes, gestures, facial expressions, into- 
i Mental Evolution in Man, p. 294. 
2 See The Encyclopaedia Brittanica, 9th edition, Vol. XVIII, pp. 
766-722, article on philology. 
3 Ibid., Vol. XI, pp. 37-43, article on Grammar. 
4 See his Science of Thought. 
6 See, among others of his writings, his essay on the Evolution of 
Language; Trans, of the Anthropological Soc. of Washington, 1880, pp. 
35-54. 
6 Essays of an Americanist, pp. 403, et seq. 
7 Essentials of Logic, pp. 82-86. 
sLeFevre (See his Race and Language, p. 42) has attempted to show 
that in phylogenesis all the grammatical categories have developed from 
the primitive cry. The cry of animals, even, (contains the roots of 
human speech. There is the cry of need which gives rise in time to 
our interjection, and later to the elements of the sentence. The warn¬ 
ing or summoning cry in turn gives rise to our demonstrative roots, and 
is the origin of the names of numbers, sex, and distance. 
9 The Mental Development of a Child; Psych. Rev. 1896 (Mono. Supp. 
No. 3). 
ioFirst 500 days of a child’s life; Child Study Mo., Vol. II, p. 607 
(March, 1897). 
41 Fundamentals of Child Study, p. 236. 
