Abby has a lot to say.

A lot.

About how the cardinal mascot at her elementary school couldn’t open the door. (“It has wings, not arms,” she explained. “It’s a bird. A red bird. But it’s not real.”) About how she sometimes helps push her little sister, Olivia, 4, uphill on her bike. (It’s got training wheels.) About how she’s already won six medals. (“I got a plastic medal, but I still count it.”)

So she’s not going to let the slight lisp (from where she’s missing a few front teeth) get in her way.

She won’t slow her pace, either, which mom Christine Cahill estimates at a 10-minute mile, 9.4 in races. Impressive for a 6-year-old. Amazing for a little girl who wasn’t even expected to walk.

Abby, of course, takes it all in stride, gabbing as she jogs beside Christine, always racing to beat Mom to the finish line. On their longer runs — the 5Ks — Christine offers to do the talking so Abby won’t get winded. “I tell her that I’ll talk and she can just listen.”

It’s an offer that Abby can refuse.

“I just like to talk, and I can’t waste a minute without talking,” she said. “I get tired sometimes when I’m talking and running, but I still do it.”

The first-grader with the silly giggle and blond bob has been running — and talking — with her mother for more than a year now. In their bright-colored running outfits and rainbow-colored shoes, they’ve become a familiar sight on sidewalks and trails around their Plymouth home. Kids on BMX bikes greet them by name as they pass, as if the mother-daughter duo were no big deal.

But every step they take together is another little miracle.

Abby was born with a life-threatening brain condition called hydrocephalus. (“I had too much stuff in my head, and they had to drain it,” is how Abby explains it.) She’s had three surgeries, but she still struggles with her vision, balance and coordination. She gets regular physical therapy, but still can’t do some of the things other kids her age do — gymnastics, contact sports. She can ride her blue-and-pink bike, but she prefers to run.

“It gets kind of scary because I’m afraid of falling,” Abby said. “I don’t have any training wheels.”

But she discovered — almost by accident — that she can run.

Christine, who was in cross-country when she was in middle school and high school, started running again when she finished law school and got married. She stopped running when she was 6 months pregnant with Abby and didn’t run again until Abby was almost a year old.

Christine would run 20 miles a week when she wasn’t training for a race or a triathlon, up to 40 miles a week when she was. “It’s my only hobby,” she said.

Abby would watch her mom come and go from the living room window.

One time when Christine finished her run, Abby asked if she could run, too. So mother and daughter took a spin around the block. Soon, after every run, Christine would stop at the house and run with Abby for a block or two. Each time, “the distance just got longer and longer,” Christine said. “Sometimes we’d run to the park and play and run back.”

Then, Abby asked if they could sign up for some kids’ runs. By the time she was 5, she was running her first 5K.

Now the two have a regular schedule. “We don’t run exactly every day,” Abby said. “We go one day and take the next day off.”

Christine is quick to add that they’re not out to set any records.

“I just enjoy the time with her,” she said. “When we’re on a run, she tells me things I would never hear about.”

She doesn’t push her daughter. She doesn’t need to. Abby pushes herself. “Sometimes, when I’m running up a hill and it’s raining, I want to stop. But I say, ‘I can do this. I can do this! I CAN DO THIS!’ ” Abby said. Then she added: “I don’t say it out loud. I just say it in my head.”

Abby said her favorite run so far was the 5K in Mora, Minn., where she finished in 30:34 and won the “10 and under” age group.

Christine’s favorite was the “Miles of Smiles” Mother’s Day 5K in Maple Grove. Her husband, Jack, pushed Olivia in the stroller and Christine and Abby ran side by side. “That was the best Mother’s Day I ever had.”

Abby is convinced that she’s going to “run forever and do swimming and running forever.”

Mom isn’t so sure they’ll run through the entire winter. But she’s thrilled for her daughter, and herself.

“It has given her so much confidence,” Christine said. “When I see her face as she’s crossing the finish line, she’s just beaming. She’s so proud.

“And she’s given her mom the sweetest running partner ever.”