People don’t say the word “retard” around our family. Or not more than once.

My wife, the ever-patient high school teacher, regards such rude exclamations as teachable moments. I reach for a knife.

Thirty years ago, our first daughter was born dark blue. Minute by minute, as the doctor tried to inflate her dormant lungs, the future we’d imagined was asphyxiated.

But another future opened up, a life just as mysterious and unprescribed as any other. Our daughter has cerebral palsy and uses a wheelchair, which is to say something about her but not everything. She does not speak, but she’s got a great laugh. She’s shy but highly attentive. She is not a tragedy nor an angel. She is not a gift from a god who never gives us more than we can handle. She loves Dr. Seuss, chocolate cake and foreign accents. She is not the star in an inspirational family drama.

She is not a retard. She is our daughter.

In 2009, a group called Spread the Word to End the Word began encouraging people to stop using that demeaning slur. The group eventually brought its campaign to thousands of schools across the country. Last year, Spread the Word to End the Word shortened its name to Spread the Word and broadened its focus to advocate for greater acceptance for people with intellectual and developmental disabilities. Those efforts come together on March 4, when people around the world are encouraged to “Pledge to Spread Inclusion.”

Some may think such efforts are a little precious: the hypersensitivity of politically correct snowflakes who can’t take a joke. We heard that a few years ago, after Donald Trump mocked Pulitzer Prize-winning reporter Serge Kovaleski, who has a joint condition called arthrogryposis. Ann Coulter graciously explained that Trump wasn’t making fun of Kovaleski’s condition; he was just “doing a standard retard.”

To the extent such a grotesque “standard” has any currency in our culture, it denigrates real people and drives them into further isolation. The words we use, the images we consider relevant or common or even funny construct the world in which we move, walk and roll.

A brilliant young critic named Amanda Leduc explores this pernicious power of language in her new book, “Disfigured.” Her focus is fairy tales, those make-believe stories gathered hundreds of years ago in the forests of France and Germany, pruned to satisfy the tastes of Victorian audiences and finally polished to a high sheen by Walt Disney. They are, of course, just stories — in the same way the R-word is just a word.

Leduc follows the bread crumbs back into her original experience with fairy tales — and then explores their residual effects. Her daring approach is a hybrid of memoir, literary criticism and cultural commentary. She moves fluidly between grade-school memories and scholarly analysis. She quotes from medieval texts and TV shows. She’s equally familiar with the Brothers Grimm and the X-Men.

As a child, Leduc’s imagination was led into the magical land of beautiful princesses and princes. Like kids everywhere, she learned that good people are beautiful or, after some hardship, become beautiful, while wicked people are mad, scarred or disabled. Such are the universal narratives from which most of us construct our first aesthetics, our fantasies, even our values. “Fairy tales are among those most quintessential of stories,” she writes. “They are both a way of explaining the world around us and a method of imagining a world that is possible.”

As a pretty little girl, fairy tales offered Leduc a comfortable throne in which to nurse her fantasies, but when she was 3, a CT scan revealed an abnormality in her brain. A subsequent operation successfully removed a cyst but left her with cerebral palsy, which affected her hips and made her limp. No glass slippers for her. Gradually, she realized that she had been exiled from the kingdom of happily ever after. There were plenty of disabled characters in fairy tales — objects of villainy, comedy or pity — but no one she wanted to identify with looked like her or moved like her.

“How to argue with the very obvious able-bodied beauty of Disney’s Belle or Cinderella, or the inevitable way so many fairy-tale endings arc toward romance?” she asks. “How to recognize that it isn’t life’s divergence from this arc that is the problem, but the establishment of this arc in the first place — these able-bodied ideals, these able-bodied expectations?”

In one engaging chapter after another, Leduc articulates the dimensions of this problem. She considers various fairy tales, from “The Little Mermaid” to “The Ugly Duckling,” which she dubs “Hans Christian Andersen at his most Hans Christian Andersen.” She also quotes from and analyzes passages from her earliest medical files, discovering in the ways doctors described her condition deeply inscribed attitudes about the limited possibilities of a disabled life.

“It is inconceivable to so many that someone could be disabled and also happy,” she writes, noting that our most archetypal stories provide only two options: glamorous perfection or pitiable tragedy. Trapped in that framework, children judged physically hopeless were once abandoned to die; in more “enlightened” times, warehoused. We’ve made progress, surely, but people who fall outside the parameters of our ideals are still largely excluded. “How many lives have been smothered,” Leduc asks, “or disappeared or haven’t been allowed to flourish because of the stories we tell?”

They are, of course, just stories.

But over and over again, Leduc notes, those stories suggest that the disabled character is someone to be feared or someone to gratefully receive our charity or someone to provide us with uplift: “The beautiful cripple — so useless but so saintly.” Inevitably, “the aim of the narrative is to eradicate the disabled life rather than change the world so that the disabled life can thrive.”

Such changes are possible — and long overdue. Watch your language. Challenge your stories. Read this smart, tenacious book.

Ron Charles writes about books for The Washington Post and hosts TotallyHipVideoBookReview.com.

Disfigured

On Fairy Tales, Disability, and Making Space

By Amanda Leduc

Coach House. 253 pp. $16.95