Young children benefit from iconicity when learning novel onomatopoeia

Iconic words, especially animal onomatopoeia, are more prevalent in infant- than adult-directed speech, possibly because iconicity bootstraps word learning. However, because infants may be unfamiliar with the sounds onomatopoeia imitate, it remains unclear whether this advantage reflects greater ease of learning. Across two experiments (2024–2025, Experiment 2—pre-registered), 111 children (69 male, 98 white, 55 18-month-olds, 56 3-year-olds) were randomly allocated to congruent or incongruent groups and told onomatopoeic names for toys that matched or mismatched animal-sounds the toys made. Children were tested on their learning of toys’ names. Children learned congruent names significantly better (r ≈ .24); however, the effect was significant only for 3-year-olds. Thus, iconicity in onomatopoeia facilitates children’s word learning, possibly more strongly for older children.