English language is the expression of thought. The rules of English grammar agree with the laws of thought. In other words, grammar is usually logical. That is…its rules accord with the principles of logic which is the science of exact reasoning.
The rules of grammar do not derive their authority from logic…but from good usage. That is….from the customs or habits followed by educated speakers and writers. These customs differ among different nations and every language has therefore its own stock of peculiar constructions or turns of expression. Such peculiarities are called idioms.
Thus, in English we say…It is I. but in French the idiom is C’EST MOI which corresponds to…It is me. Many careless speakers of English follow the French idiom in this particular. But their practice has not yet come to be the accepted usage. Hence, though C’EST MOI is correct in French, we must still regard IT IS ME as ungrammatical in English. It would, however, become correct if it should ever be adopted by the great majority of educated persons.
Grammar does not enact laws for the conduct of speech. Its business is to ascertain and set forth those customs of language which have the sanction of good usage. If good usage changes, the rules of grammar must change. If two forms or constructions are in good use, the grammarian must admit them both. Occasionally, also, there is room for difference of opinion. These facts, however, do not lessen the authority of grammar in the case of any cultivated language. For in such a language usage is so well settled in almost every particular as to enable the grammarian to say positively what is right and what is wrong. Even in matters of divided usage, it is seldom difficult to determine which of two forms or constructions is preferred by careful writers.
Every language has two standards of usage….the colloquial and the literary. By COLLOQUIAL LANGUAGE, we mean the language of conversation and by LITERARY LANGUAGE, we mean that employed in literary composition. Everyday colloquial English admits many words, forms, phrases and constructions that would be out of place in a dignified essay. On the other hand, it is an error in taste to be always talking like a book. Unpractised speakers and writers should, however, be conservative. They should avoid, even in informal talk, any word or expression that is of doubtful propriety. Only those who know what they are about can venture to take liberties. It is quite possible to be correct without being stilted or affected.
Every living language is constantly changing. Words, forms and constructions become obsolete and others take their places. Consequently, one often notes in the older English classics, methods of expression which, though formerly correct, are ungrammatical now. Here a twofold caution is necessary. On the one hand, we must not criticise Shakspere or Chaucer for using the English of his own time. But, on the other hand, we must not try to defend our own errors by appealing to ancient usage.
Examples of constructions once in good use, but no longer admissible, are….
The best of the two (for “the better of the two")
The most unkindest cut of all
There’s two or three of us" (for there are)
I have forgot the map (for forgotten)
Every one of these letters are in my name (for is)
I think it be (for is)
The language of poetry admits many old words, forms, and constructions that are no longer used in ordinary prose. These are called archaisms (that is, ancient expressions). Among the commonest archaisms are thou, ye, hath, thinkest, doth. Such forms are also common in prose, in what is known as the solemn style which is modelled, in great part, on the language of the Bible.
In general, it should be remembered that the style which one uses should be appropriate, that is, it should fit the occasion. A short story and a scientific exposition will differ in style. A familiar letter will naturally shun the formalities of business or legal correspondence. Good style is not a necessary result of grammatical correctness, but without such correctness it is, of course, impossible.