Repeat after you: Contingent vocal imitation increases children's vocalizations and orienting responses

Sun et al. (2025) tested a simple move: repeat the child’s sound right after it happens. They called it contingent vocal imitation. Three children with developmental delay took part. The team compared the imitation tactic to four control conditions using an alternating-treatments design.

Every child more than doubled their vocalizations when the adult echoed their sounds. The gains showed up right away and stayed large across all sessions. Kids also looked at the adult more often during the imitation condition.

Pelaez et al. (2011) first proved the effect with infants; Sun’s 2025 study tightens the controls and shows the same jump in vocal output. Neimy et al. (2020) added motherese at home and still saw the boost, so the tactic works with or without extra baby-talk.

Ishizuka et al. (2016) moved the procedure to preschoolers with autism and again found more vocal turn-taking. Sun’s data now bridge the gap, showing the effect holds for children with broader developmental delays.

Hickey et al. (2024) taught parents to deliver the move through a short online clip. Their positive results mean you can hand this skill to families in minutes, then see the same vocal gains Sun reports.

You already have this intervention in your pocket: just echo the child’s sound within a second. No extra materials, no data sheets. Use it during play, snack, or diaper changes to build early vocal behavior. Pair it with parent training so families can keep the momentum at home.