Charles Marlow is a high school English teacher. His daughter Emmy has just left for college, his wife Alison has left him years ago, and his autistic son Cody will soon be 21, at which point he will age out of state-supported care. Charles remembers his childhood, when he attended fourth grade with a teacher obsessed with the Palmer Method of Handwriting and a strange boy named Dana McGucken.
Language Arts contains examples of:
- 20 Minutes into the Past: The book takes place in the school year of 2012-2013.
- Ambiguous Disorder: Dana is known to his classmates as a "ree-tard." In the present day, Charles's theories include ADD, ADHD, Asperger's, OCD, phenylketonuria, fetal alcohol syndrome, and Pitt-Hopkins syndrome.
- Awful Wedded Life: Charles's parents, Garrett and Rita, pretend to be happily married in public, but in private they openly loathe each other and have nightly insult-filled shouting matches.
- Blood Oath: Charles and his childhood best friend Donnie Bothwell invented their own version that involved swapping the band-aids on their scraped knees.
- Character Tics:
- Dana has a lot: he sways back and forth, stares at the ceiling or out the window, picks his nose, sticks pencils in his ears, kicks his feet, and gesticulates while grunting. After a traumatic experience when Mrs. Braxton tries to tie a ruler to his arm, he acquires a nervous habit of massaging the area between his thumb and forefinger.
- Emmy yanks her mouth sideways when she thinks.
- Cody's default position involves holding his arms raised and bent at right angles, with his fists clenched.
- Empty Nest: Charles feels sad and lonely after Emmy moves out.
- First Friend: Charles met Donnie in kindergarten after they were both knocked over by a stampede of upperclassmen and sat next to each other outside the nurse's office. They were best friends for the next four years, until the Bothwells moved to Minnesota before fourth grade.
- Grade Skipper: Emmy graduated from high school summa cum laude at age sixteen.
- Held Back in School: Some of Charles's fourth grade classmates have a hardened look that makes him think they were held back.
- Imaginary Friend: Emmy died shortly after birth. Charles imagined what her childhood would be like, writing letters to her and storing them in the crawlspace.
- Limited Wardrobe: Dana wears an oversize white linen suit with no tie to school every day.
- Maternal Death? Blame the Child!: Sister Georgia's mother died in childbirth, depriving her father of a son. Her father never forgave her.
- One-Word Vocabulary: Before Cody went entirely mute, the last word to go was "God," which became shortened to "Gaaaah." He applied that word to everything, including Emmy.
- Picky Eater: Cody has eaten the same thing for dinner every night since he was thirteen: partially thawed peas, mashed potatoes, room temperature fried chicken, and a vitamin smoothie.
- Porn Stash: When Charles was a kid, his father kept his Playboys in the garage in a footlocker which he sometimes left unlocked by accident. Charles was too young to be turned on by the models, and wondered what was so special about the magazine that it would be kept so secretively, when the cartoons weren't even funny.
- Rape as Backstory: Sister Georgia was raped by soldiers in World War II. She had a baby boy, whom she gave up for adoption.
- Scars Are Forever: Cody's torso is covered in scars from when he accidentally set himself on fire when he was ten. He can't stand to be touched there.
- Scatterbrained Senior: Sister Georgia, one of the residents of Cody's nursing home, thinks she's still working as a Catholic school teacher. She doesn't understand where all the children have gone.
- The Slacker: Before he met Alison, Charles was a pot-smoking bartender with no ambitions besides making a decent salary and sleeping with female customers.
- The Speechless: Cody has been nonverbal since he was a toddler. For a while he could write his name, but he eventually lost that ability too. Now he can only sign some letters, like D for dad.
- Stress Vomit: Charles vomits in the playground when Bradley and Mitchell sexually assault Dana.
- Switching P.O.V.: Some chapters are narrated by Charles in the third person, and some are narrated by Emmy in the first.
- Teacher's Pet: Charles becomes Mrs. Braxton's favorite student due to his excellent penmanship, earning him the hatred of the rest of the class, particularly the bullies Bradley Wilcox and Mitchell Rudd and the overachiever Astrida Pukis. Dana becomes his Only Friend.
- The Un-Smile: When Mrs. Braxton bestows a compliment upon Charles, she tries to smile, even though the muscles responsible are nearly atrophied and she's wearing a set of creepy-looking dentures.
- Why Couldn't You Be Different?:
- Alison spent Cody's childhood wasting massive amounts of money on quack cures, banning random things like plastic containers and the microwave because she'd heard they caused autism, and only allowing Cody to do things he likes, like ripping up magazines and grinding up ramen noodles with a mortar and pestle, for ten minutes a day. When Charles asks her why she can't accept him the way he is, she says "The way he is is sick," and compares him to a kid with cancer. She becomes more accepting after Cody bonds with Sister Georgia and helps her make a collage.
- Not only was Sister Georgia a girl, instead of the boy her father wanted, she was regarded as a backwards child.
- Working Out Their Emotions: Alison was hit hard by 9/11 and coped by throwing herself into aikido, to the point where Charles felt like a single parent.
