Considerable controversy exists among and between grammarians and linguists regarding the appropriate approach to English grammar.  On one side, we have the "prescriptive" (sometimes called "proscriptive") view, which, in the extreme, declares that grammar consists of a set of fixed and inviolable rules.  On the other, we have the "descriptive" view, which, in the extreme, states that grammar should reflect the practice of the people who use the language and that the prescriptive approach is dogmatic and unrealistic.  As with most such matters, the extreme positions create both practical and theoretical problems.  To apply grammar to the purpose for which it was intended – that is, as a tool for communication – we must arrive at some moderate position that is neither wholly prescriptive nor wholly descriptive.

Let us begin with a premise.  Language is dynamic, not static.  Historically, English has evolved from roots so different from the language we use today that Old English is to the modern speaker virtually a foreign language.  Over time, words have been invented and imported from other languages, other words have disappeared, and still others have significantly changed their meanings.  It is apparent to any high school student who has endeavored to read Shakespeare that Elizabethan English differs in some rather important ways from the language spoken in modern England and America.  Yet, historically, the time span between Elizabethan Engiish and modern English is short – a mere 400 to 450 years.

This historical change is most apparent in the vocabulary.  Most footnotes in the text of a Shakespearean play that has been annotated for the modern reader pertain to explaining what certain words meant to Elizabethan audiences.  Few footnotes are necessary to clarify syntax and grammar because the grammatical structure of Elizabethan English is enough like modern English that it presents no problems.

If we go further back in time, however, we will see some dramatic grammatical differences. Grammar does evolve – but at a much more gradual pace than vocabulary.  Over time, for example, we have discarded some of the forms and endings that English verbs had centuries ago, retaining only those endings that differentiate tenses and the ending for the third person present and present perfect tenses.

Nonetheless, grammar is much more static than vocabulary or semantics (word meanings). It comprises a set of structural conventions that users of a language have agreed upon so that they may understand one another.  We do not arrange words in random order but follow certain conventions because doing otherwise would make understanding difficult, if not impossible.  We also follow certain rules for signaling the relationships between words and for the forms of words (for example, the apostrophe to indicate that a noun is possessive) for the sake of clarity.  To be sure, even these rules may change over time.  For example, the current distinction between the possessive noun (using the apostrophe) and the plural noun (simply adding s, except for certain irregular nouns) is a relatively new convention.  Such changes are, however, very gradual.

To illustrate how grammatical conventions gradually change, let's look at the current debate over the word everyone. Nearly all of us agree that the word is singular in form.  Traditionally, we say "everyone is," not "everyone are."  Regarding the appropriate verb, nearly everyone is in agreement, even though the sense of everyone  is plural (all the people).  In addition, we have a fixed rule that pronouns must agree with their antecedents (the words to which they refer) in number.  We refer to a singular object as it and to a number of objects as they or them. We refer to a persom as he, she, him, or her and to a number of people as they or them.  Thus, if everyone is singular, and a singular antecedent requires a singular pronoun, "Everyone must do their own homework" is incorrect.  It must be "Everyone must do his or her own homework."  (In a quite recent development – the effort to make language gender-neutral – we have precluded the option of using he, him, or his to refer to an antecedent that could be either gender.)

At this point, many users of the language balk; to them, "Everyone must do their own homework" is not merely acceptable but so commonplace that it is preferred.  They are joined in this assertion by many grammarians and linguists, including some grammarians who are ordinarily rather strict prescriptivists.  Indeed, the tide supporting "Everyone must do their own homework" has risen considerably since the insistence on "genderless" prose has made it unacceptable to use "Everyone must do his own homework."  Most of us find the use of "he or she" and "his or her," especially when these phrases occur frequently, to be awkward and tedious.  Therefore, it seems very likely that the use of a plural pronoun to refer to everyone will become grammatically acceptable – even though we retain a singular verb.  Although "Everyone has [singular] done their [plural] homework" is essentially inconsistent, treating everyone as both a singular and plural element, such a construction will likely prevail.

Extremists in the prescriptive camp may object that such a practice violates a sacrosanct rule of pronoun-antecedent agreement.  Extremists in the descriptive camp may declare that this exception proves that traditional grammar has no validity.  However, all this example proves is that, where there is substantial reason to do so, we should be flexible enough to bend the traditional rules.  It does not support the proposition that traditional grammar is meaningless or archaic, nor does it imply that we should abandon all the other conventions for pronoun-antecedent agreement. To discard a set of rules because they contain an exception is utter foolishness.

On the other hand, we must be cautious about the exceptions that we allow.  Again, an example is instructive.  Many people utter such statements as "Mary and me are friends," whereas conventional grammar insists, categorically, that it should be "Mary and I are friends."  English rules of case require that any noun or pronoun that serves as the subject of a sentence must be in the nominative case.  Since English nouns take the same form in both the nominative and objective case, this rule is of no consequence with nouns, but it is important with personal pronouns because all of them (except it and you) have different forms in the nominative and objective cases.  In the sentence, "Mary and I are friends," the pronoun is the subject (it can be nothing else); thus, the appropriate form of the pronoun is I, not me.

Some in the descriptive school may argue that the second element in a compound subject (or, for that matter, a compound object) need not follow the traditional rules for case.  They may support this view on the grounds that many people break the rules whenever the subject or object is compound.  Therefore, they say, let us make an exception for all compound objects and subjects. This, of course, would lead us to accept "Them and their neighbors have many fights" and "Us and them disagree" (or is it "We and them disagree" or "Us and they disagree"?).  In the objective case, which now is to be disregarded, we would accept, "I saw Tom and she yesterday," "The Joneses sent Christmas cards to we and all their other friends," and "Give it to I or my assistant." This is madness – justified on the sole grounds that many people walk around saying, "Mary and me are friends."

At the center of this debate, we suspect, is the question of whether grammar is to be determined by majority rule or by fixed conventions.  This dilemma is not as easily resolved as we might think.  On one hand, usage is, by definition, whatever grammar people use in everyday discourse.  On the other, if we do not have some rather fixed conventions of usage and each individual's usage is as valid as the next person's (everybody has a vote), we have no consensus.  Consensus is at the very heart of communication. To begin with, we agree generally (with a few exceptions) on how letters must be arranged to form words.  We agree (albeit with considerable dialectical variation) on how these words are to sound when they are spoken.  And we agree (again with some exceptions and variations) on what these words mean. In short, we observe some rather fixed conventions because, if we didn't have them, we could not make ourselves understood.

Regarding the forms that words take and the way they relate to one another – that is, regarding grammar – we follow the same principle.  Here, however, the conventions are more complex, and the exceptions and variations are likely to be more numerous.  That is all the more reason not to hastily suspend rules that work, even if certain large groups of people do not follow them.  Intelligent dissent is permissible, but discarding whole structures that have proven to work is tantamount to linguistic anarchy.  It's somewhat like letting the teenagers in the household determine an entire set of rules to suit themselves because the rules that worked for their parents don't appeal to them.

When we get to the core of the matter, I believe that we may find that those who want to uproot traditional grammar are not motivated by such noble ideals as linguistic freedom.  They often have no better motive than to avoid having to learn the rules.  In some cases, like teenagers, they rebel simply for the sake of rebellion – not because they have anything better to offer but because they resent authority.

To the extreme prescriptivists, I say, "Be flexible.  Bending the rules where a sound basis exists for doing so is not the end of the English language as we know it."  To the extreme descriptivists, I say, "Look where you're going before you leap.  Be wary of throwing away the grammatical baby with the bathwater."  To both, I say, "Keep in mind the purpose of language – communication. If we totally ignore, or do not permit, changes in usage, grammar can become so archaic that it loses its relevance in communication.  On the other hand, if we totally ignore the rules that do exist, we will eventually have no common ground with which to communicate."

An instructive example of how compromise works over time is the use of contractions.  Years ago, when I went to school, we were taught never to use contractions in writing.  Even expressions that were commonplace in everyone's speech (don't, can't, won't) were forbidden in writing.  Along with an increase in informality in society, however, came wider acceptance of writing – even formal writing – that more closely mimicked speech.  Contractions became acceptable in virtually all but the most formal communications.  Their use nowadays is more a matter of style than of fixed rules. Relaxing the rigid standards has not hindered communication, though some more conservative people may assert that style has suffered.  That's an open topic for debate, not grounds for dogmatism.

On the other hand, the widespread use of contractions has had some negative consequences.  The most striking is that many people don't seem to know how contractions are formed, that the apostrophe represents the omission of a letter or letters when two words are merged.  At least, many students in my college composition classes do not know this; it's a "grammatical principle" that somehow gets missed. Put this lack of knowledge together with ignorance of two other principles of grammar – the way possessive pronouns are formed and the use of the apostrophe in possessive nouns (but not to form plurals of nouns) – and the results are evident.  Otherwise literate people cannot distinguish it's from its, they're from their, and you're from your, and some people write about "reading book's" or talking to "two lady's."  None of this argues that we should invoke a reactionary, prescriptive prohibition of contractions; nor does it argue that we should discard traditional rules regarding possessive pronouns or plural and possessive nouns.

As in most matters worthy of debate, the sensible position is somewhere between extremes, with flexibility to move in either direction, as the situation warrants.  If one is more a grammarian than a linguist (as is true of me), one is likely to lean toward the prescriptive end of the spectrum – but should be sensitive to changes in the language.  If one is more a linguist than a grammarian, one is likely to lean toward the descriptive approach – but must respect the necesity for traditional grammar.