# Word Learning in Reading and Language Impairment Subgroups

> **NIH NIH R01** · UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA · 2020 · $744,644

## Abstract

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Project Summary/Abstract
Children with language-based learning disabilities, including specific language impairment (SLI) and dyslexia,
comprise over 57% of children receiving special education services in public schools (> 3 million children).
Although they are separate disorders, SLI and dyslexia frequently co-occur in the same individuals. Difficulty
learning new words is considered a central feature of SLI, whereas for children with dyslexia, vocabulary
deficits are typically viewed as a byproduct, rather than a cause, of reading problems. However, most studies
of word learning in children with SLI and dyslexia have involved heterogeneous groups, which likely contain
many cases of comorbidity. Our research team has been the first to study word learning in children with SLI
who have good word reading skills (SLI-only) and children with dyslexia who have good oral language skills
(dyslexia-only) as compared to children with both SLI and dyslexia (SLI+DYS) and peers with typical
development (TD). Our convincing preliminary results suggest a paradox between experimental word learning
studies and standardized measures of vocabulary size. First, despite performing comparably to TD peers on
standardized measures of vocabulary size, children with dyslexia-only have considerable difficulty learning
novel words in experimental word-learning paradigms. Second, children with SLI-only performed significantly
better than those with dyslexia-only despite scoring significantly lower than those with dyslexia-only on
standardized measures of vocabulary size. Our long-term goal is to better understand the paradox between
experimental word-learning studies and standardized measures of vocabulary size and to inform clinical
practice with regard to the assessment and treatment of word-learning deficits as related to literacy outcomes.
In this project, we will test theory-driven, clinically relevant hypotheses about word learning and its relation to
literacy outcomes in a longitudinal study of children with SLI, dyslexia or both (SLI+DYS) compared to their TD
peers, from 2nd to 4th grade. Specific aims are: (1) to test three theory-driven factors that may explain SLI and
dyslexia subgroup differences in word-learning at 2nd grade: quantity of exposures, type of instruction, and
stages of word learning; (2) to determine the contribution of linguistic, domain-general, and home environment
measures to explain individual differences in 2nd grade word learning; and (3) to predict literacy outcomes in 4th
grade from measures of word learning in 2nd grade. These aims fill theoretical gaps regarding the mechanisms
for word-learning deficits in children with SLI and dyslexia and address methodological limitations of past
studies by considering comorbidity and including carefully selected groups of children with a range of language
and literacy abilities. Important innovations include connecting disparate lines of inquiry (experimental word
learning and academic outcomes; ...

## Key facts

- **NIH application ID:** 9983651
- **Project number:** 5R01DC017156-03
- **Recipient organization:** UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
- **Principal Investigator:** Suzanne M. Adlof
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $744,644
- **Award type:** 5
- **Project period:** 2018-07-05 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9983651

## Citation

> US National Institutes of Health, RePORTER application 9983651, Word Learning in Reading and Language Impairment Subgroups (5R01DC017156-03). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9983651. Licensed CC0.

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