'Smashing' Verb Learning through Parental Sound Symbolic Input in Preterm and Full-Term Children

Sound symbolism, the iconic link between speech sounds and meanings, helps children's verb learning. In sound symbolically rich languages such as Turkish, hearing sound symbolic words might facilitate early verb learning and later language-specific expressions of motion events, by providing an easier way to map verbs onto events. These links could be much stronger for children who had difficulties in word-referent mapping (e.g., preterm children). The current study examined the association of Turkish-speaking parents' sound symbolic input at 20 months with children's concurrent verb knowledge and later motion event descriptions at 48 months. Ninety-one parent-infant dyads (Mage = 19.92 months, SD = 1.38; 41 preterms) were observed at 20 months, where we measured sound symbolic input and verb knowledge. Sixty-four of these dyads participated in a motion event description task at 48 months (25 preterms, Mage = 48.79 months, SD = 1.68), where we coded how children use path (the trajectory of motion) and manner (how an action is performed) of a motion. Results from the robust regression models suggested that for preterm children, parents' sound symbolic input used in adverb forms was positively and concurrently related to children's verb knowledge. Only for full-term children, sound symbolic input (used as adverbs) predicted full-term children's use of both path and manner information in their descriptions at 48 months. Lack of replication of these findings with outlier-removed analyses could only suggest a trend toward the differential contributions of sound symbolic input in different child populations and the importance of sentential cues in sound symbolic input in verb learning.