either they are asleep or else they are feeling something.

All our languages are the result of art. It has long been a subject
of inquiry whether there ever was a natural language common to all;
no doubt there is, and it is the language of children before they
begin to speak. This language is inarticulate, but it has tone,
stress, and meaning. The use of our own language has led us to
neglect it so far as to forget it altogether. Let us study children
and we shall soon learn it afresh from them. Nurses can teach us
this language; they understand all their nurslings say to them, they
answer them, and keep up long conversations with them; and though
they use words, these words are quite useless. It is not the hearing
of the word, but its accompanying intonation that is understood.

To the language of intonation is added the no less forcible language
of gesture. The child uses, not its weak hands, but its face. The
amount of expression in these undeveloped faces is extraordinary;
their features change from one moment to another with incredible
speed. You see smiles, desires, terror, come and go like lightning;
every time the face seems different. The muscles of the face are
undoubtedly more mobile than our own. On the other hand the eyes
are almost expressionless. Such must be the sort of signs they use
at an age when their only needs are those of the body. Grimaces
are the sign of sensation, the glance expresses sentiment.

As man's first state is one of want and weakness, his first sounds
are cries and tears. The child feels his needs and cannot satisfy
them, he begs for help by his cries. Is he hungry or thirsty? there
are tears; is he too cold or too hot? more tears; he needs movement
and is kept quiet, more tears; he wants to sleep and is disturbed,