What is the difference between traditional grammar and modern grammar?

Answer 1

There is no difference. All grammar is traditional. There is a difference between formal or written grammar, which insists on certain distinctions, as between who and whom, the appropriate use of subjunctive and the indicative moods and agreement of subject and verb, and informal or colloquial grammar which does not. In the old days, silly teachers often mistakenly taught that an English sentence may not end with a preposition, but that was simply incorrect, not formal grammar. Today's silly teachers sometimes mistakenly teach that the pronoun I may be the object of a proposition -" Dad took my sister and I to the beach" - but that is simply incorrect, not informal grammar. Modern English grammar, as the description of modern English usage characteristic of people under the age of forty, certainly suffers from the reduction of distinctions, the loss of refinement and the tongue-tied confusion of tenses and moods which is the inevitable result of having its standards set by the most careless speakers rather than by the most careful. Traditional grammar doesn't let you write like you talk. It doesn't, among other things, let you end a sentence with a preposition or start a sentence with the word "and." Some English teachers still insist that people comply with each and every one of those archaic rules, but many writers have accepted and even recommended the use of modern grammar instead.