out of doors, she says 'hat' as she puts something on the baby's head. Being taken out becomes an interest to the child; mother and child not only go out with each other physically, but both are concerned in the going out; they enjoy it in common. By conjunction with the other factors in activity the sound 'hat' soon gets the same meaning for the child that it has for the parent; it becomes a sign of the activity into which it enters. The bare fact that language consists of sounds which are mutually intelligible is enough of itself to show that its meaning depends upon connection with a shared experience.
In short, the sound h-a-t gains meaning in precisely the same way that the thing 'hat' gains it, by being used in a given way. And they acquire the same meaning with the child which they have with the adult because they are used in a common experience by both. The guarantee for the same manner of use is found in the fact that the thing and the sound are first employed in a joint activity, as a means of setting up an active connection between the child and a grown-up. Similar ideas or meanings spring up because both persons are engaged as partners in an action where what each does depends upon and influences what the other does. If two savages were engaged in a joint hunt for game, and a certain signal meant 'move to the right' to the one who uttered it, and 'move to the left' to the one who heard it, they obviously could not successfully carry on their hunt together. Understanding one another means that objects, including sounds, have the same value for both with respect to carrying on a common pursuit.
After sounds have got meaning through connection with other things employed in a joint undertaking, they can be used in connection with other like sounds to develop new meanings, precisely as the things for which they stand are combined. Thus the words in which a child learns about, say, the Greek helmet originally got a meaning (or were
