Developmental change is key to understanding primary language impairment: the case of phonotactic probability and nonword repetition.
OBJECTIVE
In this study, the authors aimed to explore the relationship between lexical and phonological knowledge in children with primary language impairment (PLI) through the application of a developmental methodology. Specifically, they tested whether there is evidence for an impairment in the process of phonological abstraction in this group of children over and above that which would be predicted by their vocabulary growth.


METHODS
The authors measured developmental change in the abilities of typically developing (TD) children ( n = 38, chronological age [CA] = 3;0-5;6 [years;months]) and those with PLI ( n = 13, CA = 3;0-6;6 and 4;6-8;0) to repeat nonwords with high and low phonotactic probability (PP) to uncover group differences in the process of abstraction of phonological representations.


RESULTS
Cross-sectional developmental trajectories of change in nonword repetition abilities were compared across CA and vocabulary growth. Unlike TD children, the children with PLI did not evince a narrowing gap in the influence of PP across development, and they reached a plateau in their development.


CONCLUSIONS
These results suggest slowed emergence of phonological representations in PLI, with a plateau in the development of lexical-phonological representations. This plateau may represent entrenchment and "fixing" due to a missed critical period and/or atypical word learning biases in PLI.
Correspondence to Cristina McKean: cristina.mckean@ncl.ac.uk.
Cristina
C
McKean
Carolyn
C
Letts
David
D
Howard
D001184:Articulation Disorders / Q000175:diagnosis / Q000503:physiopathology*; D002648:Child; D002663:Child Language; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D006801:Humans; D007804:Language Development; D007805:Language Development Disorders / Q000175:diagnosis / Q000503:physiopathology*; D007807:Language Tests; D008037:Linguistics; D008137:Longitudinal Studies; D010699:Phonation / Q000502:physiology*; D010700:Phonetics; D011336:Probability; D014706:Verbal Learning; D014825:Vocabulary
development; lexicon; nonsense words; phonotactic probability; primary language impairment; trajectory