Early Sign Language Access Linked to Strong Number Skills in Deaf Children, Study Finds

Deaf children who learn American Sign Language from birth perform on par with hearing children raised on spoken English when it comes to understanding what numbers actually mean, according to a first-of-its-kind study published in the journal Child Development. The research, led by Marie Coppola, a professor of psychological sciences and linguistics at the University of Connecticut, systematically assessed how the timing of language access, the modality of the language learned, and hearing status shape children’s grasp of a foundational mathematical concept known as the cardinal principle. The finding challenges long-standing assumptions that spoken language is the necessary route to cognitive development in deaf and hard-of-hearing children.

The cardinal principle is the understanding that the final number word said when counting a group of objects represents the total quantity of items in that set. Typically developing children usually grasp this idea between the ages of three and a half and five and a half. It is a genuine abstraction, Coppola explains: there is nothing special about the last word in the counting sequence itself, but rather the child comes to understand that the whole set is what that word describes. Achieving this milestone is considered a critical component of later mathematics proficiency, which makes early differences in how children reach it a matter of serious educational concern.

For many deaf and hard-of-hearing children, the path to that milestone is disrupted at its starting point. Fewer than 10 percent of deaf and hard-of-hearing children in the United States are born to deaf parents who use American Sign Language, meaning very few acquire language at home from birth the way most hearing children do. Many parents are instead encouraged to pursue spoken language, assistive technologies, and speech therapies, and while some deaf children do acquire spoken-language skills this way, a large number do not. Researchers have reported significant gaps between hearing and deaf and hard-of-hearing children in early language development, and even in high-income nations with strong special education infrastructure, deaf and hard-of-hearing children lag roughly one year behind their hearing peers in mathematics.

The consequences appear to cascade through later educational experiences. Deaf and hard-of-hearing students have been found to score lower on standardized mathematics assessments conducted between the ages of 8 and 16, and in 2017, 15.2 percent fewer deaf and hard-of-hearing individuals earned bachelor’s degrees compared with hearing individuals. Coppola maintains there is no fundamental reason why deaf children cannot achieve proficiency at the same rate as hearing children, and she has spent years building an evidence base for the benefits of early language access. She notes that more than 30 years of research have shown that later access to language leads to less proficient language development, and she hoped that framing the question around mathematics, in the context of growing interest in STEM education and careers, would draw wider attention.

In 2016, Coppola received a National Science Foundation CAREER Program award to test the hypothesis that access to language from birth, whether spoken English or ASL, would influence a child’s development of numeracy skills. Working with specialized schools around the United States, her team recruited deaf and hard-of-hearing students between the ages of 3 and 7, including children exposed to ASL by at least one signing parent since birth, children exposed to spoken English since birth, and children who began acquiring either language later in childhood. Recruitment was the most difficult part of the study, Coppola says, because only one to two children per thousand have a significant hearing loss around the time of birth, and of that small population only about 5 percent have deaf parents. The team therefore focused on schools with substantial numbers of native signing children, and she credits the participating programs with making the study possible.

Data collection took years and involved a team of deaf and hearing research assistants who interacted with each of the 178 children in the study. Coppola emphasizes that including proficient deaf signers was essential to giving every child the best opportunity to communicate what they knew, particularly for children who may not have had full language access earlier in life. The assessments focused largely on how well the children had grasped the cardinal principle. Researchers measured how high each child could count, both without any objects and using a board with colorful fish, extending the task in increments of ten for children who could count past ten. They recorded the highest number each child counted correctly without mistakes such as skipping numbers, saying number words out of order, or repeating them.

The children were also asked to create sets of specific quantities, which allowed the researchers to assess how well the children understood the meanings of the number words they knew and whether they had mastered the cardinal principle. The results were unambiguous. When Coppola compared hearing children learning spoken English from their parents at home with deaf children learning ASL from their parents at home, the two groups were, in her words, indistinguishable, showing totally comparable performance. The study also found that children with early access to either spoken English or ASL at home performed better on the number tasks than children exposed to language at later points in development, even after controlling for external factors including socioeconomic status.

The socioeconomic result stands out on its own. Coppola notes that in nearly any paper on mathematics development, socioeconomic status emerges as a significant factor, yet it had no impact in this study. The findings also dovetail with research from Boston University showing that deaf children of hearing parents demonstrated age-level vocabulary development when exposed to ASL by the time they were six months old. Across the dataset, regardless of how old children were when they gained good access to language, knowing how to count proved important for understanding the cardinal principle. Coppola describes this as not surprising, but as the first really hard evidence that the relationship holds for both hearing children and deaf children.

The study is the first to systematically assess how the timing of language access, the modality of language learned, and hearing status affect children’s acquisition of the cardinal principle and the ability to create sets larger than six. The researchers note that it demonstrates deafness itself does not impede numeracy development, underscoring the equivalence of early sign language and spoken language in supporting number cognition. Coppola designed the project with parents in mind, aiming to give hearing parents of deaf children concrete evidence that children exposed to ASL early in life look like typically hearing children on these measures. She points out that hearing parents can learn to sign alongside their deaf children, and that research has shown hearing parents can support age-appropriate development in this way.

The broader implications reach into early intervention practice and best-practice recommendations for deaf and hard-of-hearing children, though Coppola acknowledges that changing established approaches will take time. She is hopeful that as evidence-based work like this study gains attention, and as Deaf culture becomes more visible through social media and popular culture, the efforts of members of the Deaf Community to shift how service providers and clinicians approach deaf children’s needs will ultimately succeed. The study was coauthored by Kristin Walker of Stony Brook University, Emily Carrigan, an independent researcher based in North Carolina, and Anna Shusterman of Barnard College of Columbia University. It was supported by U.S. National Science Foundation grants 1553589, 0845966, 1420966, and 2010547, and by NSF National Research Fellowship Program Grant 2234683. The authors report no conflicts of interest.

Subject of Research: The effect of early sign and spoken language exposure on number concept development in deaf and hard-of-hearing children

Article Title: Access to ASL from birth supports childhood math proficiency in deaf children, UConn researcher finds in first-of-its-kind study

Article References: Access to ASL from birth supports childhood math proficiency in deaf children, UConn researcher finds in first-of-its-kind study. Original publication (Bibliographic details unavailable.)

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Keywords: American Sign Language, deaf children, cardinal principle, numeracy, language acquisition, Child Development, UConn, early intervention, number cognition, hearing loss, mathematics proficiency, observational study