You’ve got THIS! Demonstratives as a multimodal pathway to early word learning

Function words like `I' or `some' are highly frequent in children's linguistic input but are not learned early, so we ask: do they play any role in early word learning? Here we test a novel hypothesis that demonstratives, a class of function words like THIS and THAT in English, generate word learning opportunities for young children because they provide multimodal cues to joint attention on labeled objects. Combining head-mounted eye-tracking with machine-learning modeling of naturalistic interactions between parent and child (19 months), we show that demonstratives provide augmented inputs that scaffold word learning. Our results suggest that these function words orchestrate attentional dynamics in multimodal social interaction, expanding long-standing learning theories and showing that children can learn words from the full richness of everyday experience.