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Schulz started singing "Baby shark, doo doo doo doo doo doo" as Harper walked on the treadmill.
"I like the tune of that song. I use it like a metronome. I want her to walk to that beat. Doo doo doo! Pick up her speed, walk faster," Schulz explained to the television station.
She gained confidence walking, and that feeling has translated into her talking more.
She also is learning to use more motor skills as she “grocery shops” and plays catch at the rehab center with Schulz.
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Harper is now getting braver, tumbling and playing with her older brother Kellen, and talking to almost anyone.
"When I first saw her taking five, six, seven steps across the room, I was like 'Are you serious?,'" Fred Comparin, Harper's father, told WFTS. "She'll now just walk up to total strangers and just say, 'Hi!'"