The instability of language. Language being a social habit, it is to be expected that it should not stay fixed and changeless. The simpler physiological actions are not performed in the same way by any two individuals, and no social practice is ever performed in the same way by two members of a group, or by two different generations. In this connection writes Professor Bloomfield:
The speech of former times, wherever history has given us records of it, differs from that of the present. When we read Shakspere, for example, we are disturbed by subtle deviations from our own habits in the use of words and in construction; if our actors pronounced their lines as Shakspere and his contemporaries did we should say that they had an Irish or German brogue. Chaucer we cannot read without some grammatical explanation or a glossary; correctly pronounced his language would sound to us more like Low German than like our English. If we go back only about forty generations from our time to that of Alfred the Great, we come to English as strange to us as modern German, and quite unintelligible, unless we study carefully both grammar and lexicon.[1]
[Footnote 1: Bloomfield: loc. cit., p. 195.]
There are, in general, three kinds of changes that take place in a language. "Phonetic" changes, that is, changes in the articulation of words, regardless of the meaning they bear. This is illustrated simply by the word "name" which, in the eighteenth century was pronounced ne'm. " Analogic" changes, that is, changes in the articulation of words under the influence of words somewhat similar in meaning. The word "flash," for example, became what it is because of the sound of words associated in meaning, "crash," "dash," "smash." The third process of change in language alters not only the articulate forms of words, not only their sound, but their sense. All these changes, as will be presently pointed out, can easily be explained by the laws of habit early discussed in this book, these laws being applicable to the habit of language as well as to any other.
In the case of phonetic change, it is only to be expected that the sounds of a language will not remain eternally changeless. A language is spoken by a large number of individuals, no two of whom are gifted with precisely the same vocal apparatus. In consequence no two of them will utter words in precisely the same way. Before writing and printing were general, these slight variations in articulation were bound to have an effect on the language. People more or less unconsciously imitate the sounds they hear, especially if they are not checked up by the written forms of words. Even to-day changes are going on, and writing is at best a poor representation of phonetics. The Georgian, the Londoner, the Welshman and the Middle Westerner can understand the same printed language, precisely because it does not at all represent their peculiarities of dialect. Variant sounds uttered by one individual may be caught up in the language, especially if the variant articulation is simpler or shorter. Thus the shortening of a word from several syllables to one, though it starts accidentally, is easily made habitual among a large number of speakers because it does facilitate speech. In the classic example, pre-English, "habeda" and "habedun" became in Old English, "hæfde" and" hæfdon," and are in present English (I, we) "had."[1] In the same way variations that reduce the unstressed syllables of a word readily insinuate themselves into the articulatory habits of a people. In the production of stressed syllables, the vocal chords are under high tension and the breath is shut in. It is easier, consequently, to produce the unstressed syllables "with shortened, weakened articulations... lessening as much as possible all interference with the breath stream."[2] Thus "contemporaneous prohibition" becomes "k?temp?'?ejnj?s p?h?'bif?." Sound changes thus take place, in general, as lessenings of the labor of articulation, by means of adaptation to prevailing rest positions of the vocal organs. They take place further in more or less accidental adaptations to the particular speech habits of a people. That is, those sounds become discarded that do not fit in with the general articulatory tendencies of a language. Of this the weakening of unstressed syllables in English and palatalization in Slavic are examples.[1*]
[Footnote 1: Bloomfield: loc. cit., p. 211.]
[Footnote 2: Ibid., p. 212.]
[Footnote 1*: Ibid., p. 218.]
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.