Iconic words may be common in early child interactions because they are more engaging

Spoken vocabularies contain a substantial number of iconic words, and a complete account of language evolution must explain how and why this is the case. Iconicity is especially prevalent in early communication, with one hypothesis being that this is because it scaffolds word learning by helping infants to establish referentiality, and another being that the phonological simplicity of iconic words makes them more pronounceable for infants. This study develops methods to examine whether another function of iconicity could be that it increases infants’ engagement in interactions because there is something inherently fun about iconic communication. Iconicity ratings were assigned to transcribed words in a mother’s utterances in 41 sessions with her infant between the ages of 12 and 24 months (from the Providence corpus (Demuth et al., 2006; MacWhinney 2000)). High and low iconicity bouts were identified by calculating the rolling average of iconicity per 5 words and focusing on those utterances with the highest and lowest averages. Key features from 58 high and 58 low iconicity bouts were then coded from corresponding video. Results showed that high iconicity interactions contained more behaviors considered to be indicative of engagement: eye contact, additional paralinguistic features, joint attention, smiling/laughing, gesture, child-directed utterances, and less displacement. These preliminary findings speak to the multi-functional nature of iconicity in parent-child interactions. They suggest that iconic words might be prevalent in current spoken vocabularies because people, especially young language learners and their caregivers, find these words to be intrinsically fun and engaging.