These changes of sound in language so far discussed are made independently of the meaning of words. Other changes in articulation occur, as already noted, by analogy of sound or meaning. That is, words that have associated meanings come to be similarly articulated. This is simply illustrated in the case of the child who thinks it perfectly natural to assimilate by analogy "came" to "come." Thus the young child will frequently say, until he is corrected, he "comed," he "bringed," he "fighted." In communities where printing and writing and reading are scarce, such assimilation by analogy has an important effect in modifying the forms of words. CHANGES IN MEANING. The changes in language most important for the student of human behavior are changes in meaning. Language, it must again be stressed, is an instrument for the communication of ideas. The manner in which the store of meanings in a language becomes increased and modified (the etymology of a language) is, in a sense, the history of the mental progress of the people which use it. For changes in meaning are primarily brought about when the words in a language do not suffice for the larger and larger store of experiences which individuals within the group desire to communicate to one another. The meanings of old words are stretched, as it were, to cover new experiences; old words are transferred bodily to new experiences; they are slightly modified in form to apply to new experiences analogous to the old; new words are formed after analogy with ones already in use. A simple illustration of the application of a word already current to a wider situation is the application of the word "head" as a purely objective name, to a new experience, which has certain analogies with the old; as when we speak of a "head" of cabbage, the" head" of an army, the "head" of the class, or the "headmaster." In many such cases the transferred meaning persists alongside of the old. Thus the word "capital" used as the name for the chief city in a country, persists alongside of its use in "capital" punishment, "capital" story, etc. But sometimes the transferred meaning of the word becomes dominant and exclusive. Thus "disease" (dis-ease) once meant discomfort of any kind. Now it means specifically some physical ailment. The older use has been completely discarded. To "spill" once meant, in the most general sense, to destroy. Now all the other uses, save that of pouring out, have lapsed. "Meat" which once meant any kind of nourishment has now come to refer almost exclusively (we still make exceptions as in the case of sweetmeat) to edible flesh. Whenever the special or novel application of the word becomes dominant, then we say the meaning of the word has changed.