The shuttle begins to move. The toddler is secure between his father’s hands, and he bends at the knees and pops back up again and again in front of the subway window. The parents talk idly, gazing at each other, their voices too soft to be heard over the clack of wheels, rustle of people. The child bobs between them, seized with joy at the sight of the world in fast-forward. The shopping bags at the mother’s feet must contain boxes of cereal upon boxes of medicine upon boxes of diapers. The couple ends their respective sentences and in the companionable silence, the child says Mama, and his father looks at his wife, and says the same thing, slower, as if he were the one being taught how to speak.