Pedagogy in the speech-gesture couplings of caregivers: Evidence from a corpus-based analysis.

In face-to-face communication, representational gestures-imagistically evoking properties of referents-support both language comprehension and development. In adult-adult interaction, representational gestures are systematically produced before the words they are semantically related to and support prediction of upcoming words by addressees. It is unknown whether this timing relationship also holds for caregiver-child communication. We annotated representational gestures from a corpus (ECOLANG) of semi-naturalistic conversations between caregivers and their 3-4-year-old children (929 gestures from 38 caregivers, each contributing approximately 30 min of conversation). While gestures were initiated before the onset of the semantically-related words, we found a variable relationship between the timing of the stroke (the meaningful part of a gesture) and the speech: for words more frequently used in language to young children, gesture strokes tended to be produced before the word's onset; however, for less frequent words, they tended to be produced at the same time or after word onset. Thus, caregivers dynamically adjust their gestures based on word-familiarity for their child. We suggest that these spontaneous adjustments by caregivers may support the child's ability to predict upcoming familiar words and provide semantic enrichment for unfamiliar, yet to-be-learnt words.