Our findings show that while some individual behaviours help (e.g., high pitch during novel word labelling), it’s largely the interactions between behaviours that predict learning. This suggests that multimodal communication acts as a coordinated system supporting children’s lexical development.

Using the ECOLANG Corpus, we examined how caregiver’s verbal and non-verbal behaviours (such as label repetitions, MLU, pitch, gaze, gestures, pointing) during object play shape children’s immediate word learning and vocabulary growth over time.