KU News Release

KU researcher finds most, but not all, late-talking toddlers catch up

Mabel Rice

LAWRENCE — The world’s largest study to date on language emergence has shown that 80 percent of children with language delays at age 2 will catch up by age 7. But this also means that for one in five late-talking toddlers, language delays persist.

The findings are part of a 10-year multiple-study research project directed by Mabel Rice, the Fred and Virginia Merrill Distinguished Professor of Advanced Studies and director of the Center for Biobehavioral Neurosciences in Communication Disorders at the Life Span Institute at the University of Kansas. Funding for Rice’s research comes from the National Institute on Deafness and Other Communication Disorders, one of the National Institutes of Health, and totals nearly $6 million.

Since 2002, Rice has worked with colleagues at Curtin University in Perth, Australia, to study the language development of single and twin children in the western part of the country. Their goal is to pinpoint possible environmental, neurodevelopmental or genetic risk factors in children with Specific Language Impairment.

Published in the April issue of the Journal of Speech, Language and Hearing Research, the most recent project showed that a late start doesn’t necessarily predict ongoing language problems. Beginning with a study of 1,766 toddlers, the researchers found that boys are three times as likely as girls to be late-talking toddlers. Yet when the children were 7 years of age, no differences were found between girls and boys.

“Obviously some kind of mechanism kicks in for the boys,” Rice said. “Between the age of 2 and 7, they actually learn language faster than girls. After age 7, boys and girls stay on the same trajectory.”

Rice thinks the findings give a mixed message to parents worried about their child’s language development.

“For children who are still late talkers in school, it is important to provide early intervention and enrichment,” Rice said. “Parents should contact a speech pathologist if they have any concerns.”

According to Rice, by age 2, children should have a vocabulary of about 50 words and be starting to combine those words in two- or three-word sentences. A child with Specific Language Impairment scores within the normal range for nonverbal intelligence and has no hearing loss. Motor skills, social-emotional development and the child’s neurological profile are all normal. The only noticeable gap is in language development.

The data in her latest study also show that a mother’s education, income, parenting style and mental health does not predict when a child will start to talk. This seems to debunk the widely held belief that parents or a poor home environment are to blame for a late-talking toddler, according to Rice.

“In our large and diverse sample, children in families with limited means have as good a chance at starting to talk as those in families with lots of resources,” said Rice.

In the next phase of her research, Rice will study language development in twins, collaborating with a medical geneticist at the University of Nebraska Medical Center, to look for a genetic basis of Specific Language Impairment.

Rice said the children in the data pool in western Australia are similar to Kansas children, both ethnically and socioeconomically. Rice’s studies are, in fact, using the largest language data pool ever collected that is representative of Kansas families.

Rice is one of the 146 scientists from 20 academic departments affiliated with the Life Span Institute at KU. The Life Span Institute is one of the largest research and development programs in the nation for the prevention and treatment of developmental disabilities. The institute includes 13 centers and more than 140 programs and projects located on the Lawrence campus and KU Medical Center in Kansas City, Kan., and in Overland Park and Parsons.

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