The playground was bustling with laughter and movement, but my boys, then just two and four years old, played in their own quiet way. After a speech therapy session, we stopped at a nearby park, a familiar part of our speech therapy routine when the weather was nice. My older son wandered the perimeter of the playground and discovered sweet gum balls—a spiky green fruit on the gumtree but which dries out and turns brown and drops to the ground.