Children learn language strikingly fast: By the time they can run down the street, typically developing children are already producing over a thousand words. Yet, these children who astonish us with their effortless language learning continuously forget where they leave their coats and hats. This fundamental puzzle guides my research program: How do children learn language so rapidly even though their memories, attentional control, and information processing systems are still developing? My work aims to resolve this puzzle by modeling language acquisition as a coordination problem between children and their caregivers. The problem to understand is not how children learn language, but how children and their caregivers construct it together.
Children are inundated with language from a variety of sources from parents to conversations between family members to the television in their living rooms. However, research shows that the speech that matters most is the speech directed to children by their caregivers. Infant-directed speech differs systematically from the speech that adults produce to each-other: Pitch contours are more pronounced, sentences are shorter, and repetitions are more frequent. Infants not only prefer to listen to child-directed speech, they learn better from it. Why do we talk this way to infants even if we are not intending to teach them? My research program explores the hypothesis that the pressure to maintain a child’s attention and communicate successfully results in supportive linguistic input. Even if we just want a child to stop crying, or to wipe their nose, we need to tell them in a way they understand – a way that must be coordinated to their individual cognitive and linguistic development. Together, these many moments of coordination add up to language learning.
My research program investigates this coordination from both directions, analyzing the basic cognitive processes that children bring to language learning as well as the way that caregivers structure information for their developing learners. (1) The first line of my work studies how children’s developing attentional and information processing systems control the information they have available to learn from. (2) The second line of my work examines the representations and algorithms that children bring to bear on this to discover the meanings of words. (3) The third line of my work characterizes the natural ecological contexts in which language acquisition occurs, showing how coordination between learner and environment lead to the right kind of information becoming salient for the attentional system and ultimately learning. (4) Finally, the newest work in my lab is developing a framework for studying language acquisition in interaction, probing the child’s active role in structuring the communicative exchanges in which language learning happens.
The goal of this work is an understanding of both why language acquisition is typically so rapid, and why it is sometimes delayed. Successes (and failures) of learning must emerge from the coordination between cognitive constraints and learning environment. My work explores how changes in children’s attention, memory, auditory and visual processing, and social interaction connect to each-other, and how they interact to produce acquisition.