It is a very early instinct of language; for ancient poetry is almost as free from tautology as the best modern writings. The speech of young children, except in so far as they are compelled to repeat themselves by the fewness of their words, also escapes from it. When they grow up and have ideas which are beyond their powers of expression, especially in writing, tautology begins to appear. In like manner when language is 'contaminated' by philosophy it is apt to become awkward, to stammer and repeat itself, to lose its flow and freedom. No philosophical writer with the exception of Plato, who is himself not free from tautology, and perhaps Bacon, has attained to any high degree of literary excellence.
To poetry the form and polish of language is chiefly to be attributed; and the most critical period in the history of language is the transition from verse to prose. At first mankind were contented to express their thoughts in a set form of words having a kind of rhythm; to which regularity was given by accent and quantity. But after a time they demanded a greater degree of freedom, and to those who had all their life been hearing poetry the first introduction of prose had the charm of novelty. The prose romances into which the Homeric Poems were converted, for a while probably gave more delight to the hearers or readers of them than the Poems themselves, and in time the relation of the two was reversed: the poems which had once been a necessity of the human mind became a luxury: they were now superseded by prose, which in all succeeding ages became the natural vehicle of expression to all mankind. Henceforward prose and poetry formed each other. A comparatively slender link between them was also furnished by proverbs. We may trace in poetry how the simple succession of lines, not without monotony, has passed into a complicated period, and how in prose, rhythm and accent and the order of words and the balance of clauses, sometimes not without a slight admixture of rhyme, make up a new kind of harmony, swelling into strains not less majestic than those of Homer, Virgil, or Dante.
One of the most curious and characteristic features of language, affecting both syntax and style, is idiom. The meaning of the word 'idiom' is that which is peculiar, that which is familiar, the word or expression which strikes us or comes home to us, which is more readily understood or more easily remembered. It is a quality which really exists in infinite degrees, which we turn into differences of kind by applying the term only to conspicuous and striking examples of words or phrases which have this quality. It often supersedes the laws of language or the rules of grammar, or rather is to be regarded as another law of language which is natural and necessary. The word or phrase which has been repeated many times over is more intelligible and familiar to us than one which is rare, and our familiarity with it more than compensates for incorrectness or inaccuracy in the use of it. Striking expressions also which have moved the hearts of nations or are the precious stones and jewels of great authors partake of the nature of idioms: they are taken out of the sphere of grammar and are exempt from the proprieties of language. Every one knows that we often put words together in a manner which would be intolerable if it were not idiomatic. We cannot argue either about the meaning of words or the use of constructions that because they are used in one connexion they will be legitimate in another, unless we allow for this principle. We can bear to have words and sentences used in new senses or in a new order or even a little perverted in meaning when we are quite familiar with them.
