Predicting Vocabulary Growth in Children With and Without Specific Language Impairment: A Longitudinal Study From 2;6 to 21 Years of Age Purpose Children with specific language impairment (SLI) often have vocabulary impairments. This study evaluates longitudinal growth in a latent trait of receptive vocabulary in affected and unaffected children ages 2;6 (years;months) to 21 years and evaluates as possible predictors maternal education, child gender, and nonverbal IQ. Method A ... Research Article
Research Article  |   April 01, 2015
Predicting Vocabulary Growth in Children With and Without Specific Language Impairment: A Longitudinal Study From 2;6 to 21 Years of Age
 
Author Affiliations & Notes
  • Mabel L. Rice
    University of Kansas, Lawrence
  • Lesa Hoffman
    University of Kansas, Lawrence
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to Mabel L. Rice: mabel@ku.edu
  • Editor: Rhea Paul
    Editor: Rhea Paul×
  • Associate Editor: Shelley Gray
    Associate Editor: Shelley Gray×
Article Information
Development / Language Disorders / Specific Language Impairment / Language / Research Articles
Research Article   |   April 01, 2015
Predicting Vocabulary Growth in Children With and Without Specific Language Impairment: A Longitudinal Study From 2;6 to 21 Years of Age
Journal of Speech, Language, and Hearing Research, April 2015, Vol. 58, 345-359. doi:10.1044/2015_JSLHR-L-14-0150
History: Received June 2, 2014 , Revised September 14, 2014 , Accepted November 12, 2014
 
Journal of Speech, Language, and Hearing Research, April 2015, Vol. 58, 345-359. doi:10.1044/2015_JSLHR-L-14-0150
History: Received June 2, 2014; Revised September 14, 2014; Accepted November 12, 2014
Web of Science® Times Cited: 5

Purpose Children with specific language impairment (SLI) often have vocabulary impairments. This study evaluates longitudinal growth in a latent trait of receptive vocabulary in affected and unaffected children ages 2;6 (years;months) to 21 years and evaluates as possible predictors maternal education, child gender, and nonverbal IQ.

Method A sample of 519 participants (240 with SLI; 279 unaffected) received an average of 7 annual assessments for a total of 3,012 latent trait Peabody Picture Vocabulary Test (PPVT) observations. Unconditional and conditional multilevel growth models were estimated to evaluate growth trajectories and predictor relationships over time.

Results Children with SLI had lower levels of receptive vocabulary throughout the age range assessed. They did not close the gap with age peers. Children with higher nonverbal IQs had better PPVT performance, as did children of mothers with higher education. Child gender showed an advantage for young girls that leveled out with age and then became an advantage for boys from ages 10 to 21 years. All children's rate of vocabulary acquisition slowed around 12 years of age.

Conclusions The outcomes of the study have implications for hypothesized causal pathways for individual differences; predictions differ for children under 5 years, 6–10 years, and later ages.

Acknowledgments
This work was made possible by National Institutes of Health Grants RO1DC001803, P30DC005803, and P30HD002528 awarded to Mabel L. Rice. We express special appreciation to Denise Perpich for her data management of the longitudinal study. We thank the children and families who participated in the study and appreciate their long-term commitment to the research project.
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