Changes in grammar
What’s striking about grammar rules from forty years ago is how similar they are to today’s. The guidelines for subject-verb agreement, pronoun case, modifier placement and verb tense are virtually unchanged. Many of the old rules that we now see as outdated (and that persist as grammar myths) had already toppled by 1968.
Take none, for instance. Once considered singular, none was accepted forty years ago as a plural when used in a plural sense ("None of the applicants are qualified"). The second edition of Fowler’s Modern English Usage (1965) pulled no punches: "It is a mistake to suppose that the pronoun is singular only and must at all costs be followed by singular verbs, etc.; the Oxford English Dictionary explicitly states that plural construction is commoner."
Similarly, rules drummed into earlier generations of pupils, like "don’t split an infinitive" and "don’t end a sentence with a preposition," had gone by the wayside. Eric Partridge, in the sixth edition of Usage and Abusage (1965), noted that we should avoid the split infinitive wherever possible, "but if it is the clearest and the most natural construction, use it boldly. The angels are on our side." (A different celestial phenomenon has been on our side since 1966, when the original Star Trek series aired with its now-famous "to boldly go." Interestingly, Partridge’s choice of boldly in rallying for the split infinitive predated Star Trek by one year.)
Grammarians of the day were also pooh-poohing the old prohibition against ending a sentence with a preposition. G. F. Lamb, in his textbook English for General Certificate (1964), brushed it off entirely: "The so-called ‘rule’ that we must not end a sentence with a preposition cannot be justified in English, and is not observed by any good writer." Fowler’s, in a virtual novella on the subject, concluded that the rule had become "a cherished superstition."
The only real change in grammar since the late 1960s comes in an area that overlaps with usage and that, like usage, has been influenced by larger forces of society and culture. I’m referring to agreement between a pronoun and a singular antecedent like "everyone" or "each person."
The rule back then was simple: use the masculine singular pronoun ("Everyone must bring his own wine to the party"). Since then feminism has outed the sexism implicit in that choice and has put the old practice to rest. But we’ve been left with a void, one that has produced lots of rewriting ("People must bring their own wine") and lots of debate about the ungainly his or her versus the (to some) ungrammatical their. This last option is gaining ground fast and will likely win the day, though for the moment authorities are still bickering