title: Sentence-position effects on children's perception and production of English third person singular -s.
abstract: OBJECTIVE
  Two-year-olds produce third person singular -s more accurately on verbs in sentence-final position as compared with verbs in sentence-medial position. This study was designed to determine whether these sentence-position effects can be explained by perceptual factors.
  
  
  METHODS
  For this purpose, the authors compared 22- and 27-month-olds' perception and elicited production of third person singular -s in sentence-medial versus-final position. The authors assessed perception by measuring looking/listening times to a 1-screen display of a cartoon paired with a grammatical versus an ungrammatical sentence (e.g., She eats now vs. She eat now).
  
  
  RESULTS
  Children at both ages demonstrated sensitivity to the presence/absence of this inflectional morpheme in sentence-final, but not sentence-medial, position. Children were also more accurate at producing third person singular -s sentence finally, and production accuracy was predicted by vocabulary measures as well as by performance on the perception task.
  
  
  CONCLUSIONS
  These results indicate that children's more accurate production of third person singular -s in sentence-final position cannot be explained by articulatory factors alone but that perceptual factors play an important role in accounting for early patterns of production. The findings also indicate that perception and production of inflectional morphemes may be more closely related than previously thought.
authors: Department of Linguistics, University of California, Los Angeles, 3125 Campbell Hall, Los Angeles, CA 90095-1543, USA. megha.sundara@humnet.ucla.edu
authors: Megha
authors: M
authors: Sundara
authors: Katherine
authors: K
authors: Demuth
authors: Patricia K
authors: PK
authors: Kuhl
mesh_terms: D000161:Acoustic Stimulation; D002663:Child Language; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007804:Language Development; D008037:Linguistics; D008297:Male; D009146:Music; D010775:Photic Stimulation; D010988:Play and Playthings; D013060:Speech / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D013068:Speech Production Measurement