Unlocking the mysteries of language learning

How does speech from other children influence an infant’s ability to learn language? Federica Bulgarelli, assistant professor in the University at Buffalo’s Department of Learning and Instruction and Department of Psychology, has been awarded a grant from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) to explore this question.

The two-year, $275,000 project, “The influence of child-produced speech on infant language development,” aims to understand how infants process speech from older children and how it impacts their early language development.

Bulgarelli’s research will focus on the unique role child-produced speech plays, given that most studies to date have primarily examined how infants learn from adult caregivers.

“Most of what we know about language development in infants comes from what parents say to their kids, which makes perfect sense. Kids typically have one or more adults in the home, and those adults are providing a lot of the input by talking either to their infant or around their infant,” Bulgarelli said.

“But around 80% of homes in the U.S. have more than one child in them. Speech from children doesn’t sound like speech from adults. Even if a three-year-old or five-year-old is pretty easy to understand, their voices just sound different, and they potentially make some articulatory mistakes,” she added. “We are wondering how that kind of speech might influence infant language development—because infants are fascinated by older kids.”

This project has two key aims: one experimental and one naturalistic. The experimental component involves testing infants’ preferences for and recognition of child-produced versus adult-produced speech in controlled lab settings. The naturalistic component will observe language interactions between infants, their parents and older siblings during play sessions, analyzing how these dynamics shape infants’ language learning. Findings from the project are expected to inform how speech from other children contributes to language development and could provide insights into tailoring support for different language learning environments.

In addition, Bulgarelli has also been awarded a Language Learning Early Career Research Grant to support her project, “Searching for variability: The role of listener choice on learning new words.” This $10,000 study investigates how talker variability, or the subtle differences in how words are pronounced by different speakers, affects word learning in both preschoolers and adults.

“In this grant, we are interested in whether preschoolers and college-age students look for variability when they’re trying to learn new words. Often, in classroom settings, we’re providing kids or adults some content or material. But we know that if they get to choose what they learn about, for example, that tends to positively relate to their learning, compared to not being able to make a choice,” Bulgarelli said. “And so here, we’re asking whether both adults and preschoolers actually look for or want to hear words from multiple people when they are trying to learn them. We’re measuring who they want to hear words from, and whether that variability relates to their own learning of those words at the end.”

This project will involve a series of experiments with both adults and preschoolers to determine whether learners actively seek out variability in speech and whether doing so enhances their ability to understand and produce new words. By exploring this question, Bulgarelli hopes to shed light on how learners of different ages utilize variability in language input to maximize learning.

“These two funded projects will advance our understanding of early language development and offer important insights for language acquisition and learning. Dr. Bulgarelli, with a joint appointment in Learning and Instruction and Psychology as part of GSE’s Institute for Learning Sciences’ cluster hiring initiative, is well-positioned to make impactful contributions through these studies,” said X. Christine Wang, GSE professor and senior associate dean for interdisciplinary research.

Bulgarelli’s fascination with language development began during a pivotal moment in her adolescence. Having moved from Italy to the U.S. as a middle schooler, she vividly recalls the moment she first understood a word from a song on the radio despite not grasping the entire language.

This early experience sparked her curiosity about language learning. Her interest deepened in college when she discovered the concept of statistical learning—the process by which learners subconsciously track patterns in input, such as which syllables are more likely to form words. This blend of personal experience and academic discovery led her from bilingualism research to a broader exploration of how variability influences language learning, shaping her career trajectory and research focus.

Bulgarelli now explores these themes in the Buffalo Early Learning Lab, where she serves as director and works alongside a research team of staff and students to conduct studies to better understand how children learn. She and her team are currently recruiting families to participate in the lab’s research initiatives.

Looking ahead, she is enthusiastic about the future directions of her research and the broader impact it may have. “I’m excited not just about the questions that I get to answer but also the questions that other researchers might be able to answer given the availability of this data,” she said.

By making her data accessible, she hopes to facilitate further studies and discoveries in the field. “I’m hoping that in the future, we can carry out these studies across different settings, including UB-associated daycares and beyond, to get a more representative sample of participants.”