From woof woof to dog: Interactions between parents' use of sound symbolic words and infants' vocabulary development

Sound symbols, such as "woof woof" for a dog's barking, imitate the physical properties of their referents. Turkish is a sound symbolically rich language that allows flexible use of such words in different linguistic forms. The current study examined Turkish-speaking parents' use of sound symbolic words to their 14- and 20-month-olds and the concurrent and longitudinal relations between parents' sound symbolic input and infants' vocabulary knowledge. Thirty-four (n = 34) infants were observed at Time-1 (M-age = 14.23 months, SD = 1.11) and Time-2 (M-age = 20.30 months, SD = 1.24) during free play sessions with their parents to examine parental input. Infants' vocabulary knowledge was assessed by a parental report. Both the quantity and quality of parental sound symbolic input changed between 14 and 20 months of age. Furthermore, infants' earlier vocabulary knowledge at 14 months negatively predicted parents' later sound symbolic input at 20 months. Last, parents' sound symbolic input was positively and concurrently associated with 14-month-olds' vocabulary knowledge but was negatively and concurrently associated with 20-month-olds' vocabulary levels. These findings suggest an early interaction between infants' exposure to sound symbolic input and their vocabulary development.