Predictors of Morphosyntactic Growth in Typically Developing Toddlers: Contributions of Parent Input and Child Sex PurposeTheories of morphosyntactic development must account for between-child differences in morphosyntactic growth rates. This study extends Legate and Yang’s (2007)  theoretically motivated cross-linguistic approach to determine if variation in properties of parent input accounts for differences in the growth of tense productivity.MethodFifteen toddlers (and parents) participated. None were producing tense ... Article
Article  |   April 01, 2011
Predictors of Morphosyntactic Growth in Typically Developing Toddlers: Contributions of Parent Input and Child Sex
 
Author Affiliations & Notes
  • Pamela A. Hadley
    University of Illinois at Urbana-Champaign
    University of Illinois at Urbana-Champaign
  • Matthew Rispoli
    University of Illinois at Urbana-Champaign
    University of Illinois at Urbana-Champaign
  • Colleen Fitzgerald
    University of Illinois at Urbana-Champaign
    University of Illinois at Urbana-Champaign
  • Alison Bahnsen
    University of Illinois at Urbana-Champaign
    University of Illinois at Urbana-Champaign
  • Correspondence to Pamela A. Hadley: phadley@illinois.edu
  • Editor: Karla McGregor
    Editor: Karla McGregor×
  • Associate Editor: Courtenay Norbury
    Associate Editor: Courtenay Norbury×
Article Information
Development / Special Populations / Cultural & Linguistic Diversity / Research Issues, Methods & Evidence-Based Practice / Attention, Memory & Executive Functions / Language
Article   |   April 01, 2011
Predictors of Morphosyntactic Growth in Typically Developing Toddlers: Contributions of Parent Input and Child Sex
Journal of Speech, Language, and Hearing Research, April 2011, Vol. 54, 549-566. doi:10.1044/1092-4388(2010/09-0216)
History: Received September 30, 2009 , Accepted July 23, 2010
 
Journal of Speech, Language, and Hearing Research, April 2011, Vol. 54, 549-566. doi:10.1044/1092-4388(2010/09-0216)
History: Received September 30, 2009; Accepted July 23, 2010
Web of Science® Times Cited: 27

PurposeTheories of morphosyntactic development must account for between-child differences in morphosyntactic growth rates. This study extends Legate and Yang’s (2007)  theoretically motivated cross-linguistic approach to determine if variation in properties of parent input accounts for differences in the growth of tense productivity.

MethodFifteen toddlers (and parents) participated. None were producing tense morphemes productively at 21 months. Two dependent measures of morphosyntactic growth between 21 and 30 months were used: empirical Bayes linear coefficients at 21 months and predicted productivity scores at 30 months. Predictor variables included child sex, vocabulary, and mean length of utterance as well as 4 measures of parent language input at 21 months.

ResultsInput informativeness for tense was the most consistent predictor of morphosyntactic growth, explaining 28.3% of the unique variance in children’s linear growth coefficients at 21 months and 23.0% of the unique variance in predicted tense productivity scores at 30 months. General input measures were unrelated. Child sex explained an additional 24.7% of the variance in early linear growth. Child vocabulary at 21 months did not explain a significant proportion of unique variance.

ConclusionThe findings provide evidence that input informativeness, an abstract and distributed property of input, contributes to morphosyntactic growth.

Acknowledgments
The archival database was originally gathered as part of National Institute on Deafness and Other Communication Disorders Grant R15 DC005374, awarded to Matthew Rispoli. Analyses and dissemination were supported by National Science Foundation Grant BCS-082251, awarded to Matthew Rispoli and Pamela A. Hadley. We extend our sincere appreciation to the families that made this work possible; to Sara Belczak, Joan Horky, Brittany Jaekel, Amy Schumacher, Kristin Villa, and Kimberly Young for their assistance with transcription and coding; and to Jan Holt, Janna Oetting, and Charles Yang for their feedback on coding, data analysis, and earlier versions of this article. Portions of this article were presented at the invited workshop, “Progress in Studies of SLI,” in Lawrence, Kansas; the 2009 Symposium for Research in Child Language Disorders in Madison, Wisconsin; and the 2009 Stanford Child Language Research Forum in Berkeley, California.
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