Further, when terms of relationship come into existence it is found that they are applied not to members of one family, but to all the persons of the clan who might have stood in each particular relationship to the person addressing them.

Thus a man will address as mother not only his own mother, but all the women of his clan who might have stood to him in the relation of mother.

Similarly he will address all the old men and women as grandfather or grandmother or aunt, and the boys and girls of his own generation as brother and sister, and so on.

With the development of the recognition of the consanguineous family, the use of terms of relationship tends to be restricted to persons who have actual kinship; thus a boy will address only his father's brothers as father, and his cousins as brothers and sisters; but sufficient traces of the older system of clan kinship remain to attest its former existence.

But it seems also clear that some, at least, of the terms of relationship were first used between persons really related; thus the word for mother must have been taught by mothers to their own babies beginning to speak, as it is a paramount necessity for a small child to have a name by which to call its mother when it is wholly dependent on her; if the period of infancy is got over without the use of this term of address there is no reason why it should be introduced in later life, when in the primitive clan the child quickly ceased to be dependent on its mother or to retain any strong affection for her.