The impact of baby sign on vocabulary development

Baby sign programs aim to support communication between parents and preverbal infants by pairing signs with spoken words. This study addresses a notable gap in the literature by evaluating the large-scale impact of baby sign on both lexical development and caregiver behavior. Using an online questionnaire in 1348 typically developing, French hearing children (50% female) aged 10 to 28 months, 723 children exposed to baby sign at home were compared with 625 non-exposed peers. After controlling for socioeconomic status and parent–child activities, results revealed weak to no effect of baby sign on vocabulary development or caregiver behavior. These findings suggest that while baby sign is not detrimental to vocabulary development, it does not enhance spoken vocabulary as often claimed.