All infants learn language, but they don’t all learn at the same pace. University of Iowa psychology professor Julie Gros-Louis recently received a $230,381 grant from the National Science Foundation to study the prelinguistic interactions between infants and their caregivers, and how these interactions lead to word learning and language development.

Her research publicized last year showed that infants whose parents positively respond to their babbling produced more advanced syllable-like sounds than those whose parents directed their infants’ attention elsewhere.

Her new study seeks to delve further into exactly how this parent responsiveness supports word learning in everyday interactions by connecting parent responses to infants’ visual attention and later language development.

“Previous studies have shown that caregiver responses matter for language development, but it’s not clear how they do,” Gros-Louis said.

Her research will involve coding minute-by-minute interactions between mothers and fathers and their 6- to 12-month infants to note how the parents respond to infant vocalizations, and how infants’ behavior is affected by responses, such as what the infants are looking at, subsequent vocalizations, etc. Language questionnaires will then be given at 15 and 24 months of age to determine how these interactions affect word learning.

“We know infants will develop language unless they have some inability to learn and produce sounds, but there’s such variability in when they achieve milestones and how quickly they learn words,” Gros-Louis said. “One of the biggest motivations for me is understanding this variability, which is something that people might take for granted.”

Early achievement of language milestones can predict children’s language outcomes years later, and some studies have even related those milestones to reading abilities in early elementary school.

Gros-Louis’s research could inform interventions for kids who are at risk of language delay and reveal strategies for parents to use in interactions with their infants.