How a person teaches grammar depends on what he or she believes it does. Some see grammar as a set of rules, inherited from wise forefathers. For them, teaching grammar means making students aware of, and then holding them to, these rules. Others see grammar as an expression of style, an invitation to the writer to explore how to create a distinctive voice. For teachers, the more rule-bound approach can be off-putting, suggesting to students that writing is less about communicating a thought than constructing a paper. "Garner's Modern American Usage" defines the first group as prescriptivists and the second as descriptivists. Prescriptivists see themselves as guardians of the language, William Safire types who write columns reminding people how they are supposed to talk. For them, language instruction is about maintaining an established order, something like the French Academy, which prescribes its nation's speech. This is the philosophical opposite of the descriptivists, who believe language evolves, incorporating new idioms, birthing and retiring words. They are less interested in prescribing correct speech than in describing how language changes. This is an important distinction for teachers, because the dominance of grammar drills, rote memorization, and heavy markdowns for "incorrect" grammar suggest how much prescriptive thinking dominates the classroom. Teaching from a descriptivist approach to grammar, the author suggests an assignment that engages students in research and discussion about grammatical options and effects.