Summary: The specific kinds of words toddlers learn first—especially nouns organized by shared shape—can help predict which children will have ongoing language difficulties.
Source: University of Miami
Researchers led by Associate Professor Lynn Perry report that the types of words children acquire early in life can serve as an early indicator of later language outcomes.
In a paper titled “Late bloomer or language disorder? Differences in toddler vocabulary composition associated with long-term language outcomes,” published in Developmental Science, the team shows that the proportion of shape-based nouns in a toddler’s vocabulary—words that name objects with a common shape such as cup, ball, or spoon—distinguishes children who eventually catch up (late bloomers) from those whose delays persist.
“Some children who are slow to begin talking as toddlers later develop typical vocabularies; we call these children late bloomers,” said Perry, a child language researcher in the Department of Psychology. “However, other late talkers do not catch up, and until now it’s been difficult to predict, early on, which children will follow which path.”
The study set out to identify early markers that separate late bloomers from children with persisting language delays, a distinction that matters because ongoing delays can signal developmental language disorder (DLD). Approximately seven percent of the population is affected by DLD, a common but under-recognized condition characterized by persistent difficulties with language that often go undiagnosed until school age.
“DLD causes lifelong language difficulties for many children, yet early prediction is challenging,” said co-author Sarah Kucker, an assistant professor of psychology. “Our goal was to test whether the composition of a toddler’s vocabulary—specifically how many shape-based nouns they know—could predict later outcomes.”
The researchers analyzed large, well-documented datasets tracking vocabulary development for more than 800 children across three groups: children who were late talkers in toddlerhood but later developed typically sized vocabularies (late bloomers); children who were late talkers and continued to show vocabulary delays months later (persisting late talkers); and children with typically sized vocabularies at both time points.
Using parent-report measures collected when children were about 16 months and again near 28 months, the team measured how many of each child’s known words were shape-based nouns, while controlling for overall vocabulary size. They found that, at around 16 months, children who would go on to have persisting delays already knew a smaller proportion of shape-based nouns compared with both late bloomers and typical talkers.
A subgroup of participants was followed through age seven to identify formal diagnoses. Children who later received a diagnosis of DLD also had a lower proportion of shape-based nouns in their vocabulary during the second year of life compared with children who developed typically or who later had other diagnoses, such as dyslexia.
These findings suggest that early vocabulary composition—beyond simple vocabulary size—provides useful information about a child’s risk for long-term language difficulties. The authors note that learning many shape-based nouns appears to support a “shape bias,” an attention to object shape that helps children generalize new nouns and speeds vocabulary growth. Children who know fewer shape-based nouns may be less likely to develop this bias and therefore may experience slower subsequent word learning.
Perry and colleagues emphasize the practical implications for parents, early educators, and speech-language pathologists. “Identifying children who are likely to need extra support sooner could make a real difference,” Perry said. “Targeted efforts that encourage learning of shape-based words in late talkers might help promote more typical vocabulary growth and reduce the chance of persistent language problems.”
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Author: Press Office
Source: University of Miami
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Original Research: Closed access. “Late bloomer or language disorder? Differences in toddler vocabulary composition associated with long‐term language outcomes” by Lynn K. Perry et al., Developmental Science
Abstract
Late bloomer or language disorder? Differences in toddler vocabulary composition associated with long‐term language outcomes
Children who show early delays in expressive language, commonly labeled late talkers, follow varied developmental trajectories. Some are late bloomers and eventually “catch up” to age-expected language levels; others continue to experience delays or are later diagnosed with developmental language disorder (DLD). Early in development it is difficult to predict which trajectory a child will follow.
This retrospective analysis of 850 children compared vocabulary composition in toddlerhood across groups with different long-term outcomes. Prior literature shows that typically developing children tend to have vocabularies rich in names for categories organized by shape (for example, cup), and that this pattern supports a shape-based generalization bias linked to faster vocabulary growth. Previous work also found that, as a group, late talkers say fewer shape-based category names and are less likely to demonstrate a shape bias compared with typical peers.
In the current study, toddlers who later showed persisting delays used a smaller proportion of shape-based nouns at Time 1 (13–27 months) than both typically developing children and late bloomers who achieved typical vocabulary sizes by Time 2 (18–38 months). Furthermore, children later diagnosed with DLD (between ages 4 and 7) had significantly fewer shape-based nouns in their second-year vocabularies than both typically developing children and children later diagnosed with other conditions (e.g., dyslexia).
These results offer new insight into sources of heterogeneity among late talkers and propose vocabulary composition—particularly the proportion of shape-based nouns—as a promising early metric to assess risk for long-term language difficulties.