title: Differentiating the effects of phonotactic probability and neighborhood density on vocabulary comprehension and production: a comparison of preschool children with versus without phonological delays.
abstract: OBJECTIVE
  To differentiate the effect of phonotactic probability from that of neighborhood density on a vocabulary probe administered to preschool children with or without phonological delays.
  
  
  METHODS
  Twenty preschool children with functional phonological delays and 34 preschool children with typical language development completed a 121-item vocabulary probe in both an expressive and receptive response format. Words on the vocabulary probe orthogonally varied on phonotactic probability and neighborhood density but were matched on age of acquisition, word frequency, word length, semantic set size, concreteness, familiarity, and imagability.
  
  
  RESULTS
  Results show a Phonotactic Probability x Neighborhood Density interaction with variation across groups. Specifically, the optimal conditions for typically developing children were rare phonotactic probability with sparse neighborhoods and common phonotactic probability with dense neighborhoods. In contrast, only rare phonotactic probability with sparse neighborhoods was optimal for children with phonological delays.
  
  
  CONCLUSIONS
  Rare sound sequences and sparse neighborhoods may facilitate triggering of word learning for typically developing children and children with phonological delays. In contrast, common sound sequences and dense neighborhoods may facilitate configuration and engagement for typically developing children but not for children with phonological delays because of their weaker phonological and/or lexical representations.
authors.affiliation: Department of Speech-Language-Hearing: Sciences & Disorders, University of Kansas, 3001 Dole Human Development Center, 1000 Sunnyside Avenue, Lawrence, KS 66045-7555, USA. hstorkel@ku.edu
authors.forename: Holly L
authors.initials: HL
authors.lastname: Storkel
authors.forename: Junko
authors.initials: J
authors.lastname: Maekawa
authors.forename: Jill R
authors.initials: JR
authors.lastname: Hoover
mesh_terms: D002648:Child; D002675:Child, Preschool; D032882:Comprehension; D005260:Female; D006801:Humans; D007804:Language Development; D007805:Language Development Disorders / Q000523:psychology*; D007858:Learning; D008297:Male; D010700:Phonetics; D013060:Speech; D013067:Speech Perception; D014825:Vocabulary