Maillart & Parisse (in press) found out that French children with specific language impairment (SLI) present strong difficulties in phonology when compared with normally-developing children matched by MLU (NLD). Some of the youngest children from this study were followed to provide developmental information about their language deficit. Children were tested again in the same way as before (free spontaneous production) and matched by MLU against other NLD children.
The previous phonological analysis was extended to include syntax as well as phonology. Percentage of word corrects was computed for both phonology and syntax. An analysis of covariance was performed with children's age as covariate. Results showed a significant difference between SLI and NLD children for phonology but not for syntax. There was a trend that showed that the difference between SLI and NLD children tended to increase with age. Absence of significant results was explained by a very large variability in syntactic results (contrary to phonology and to results for NLD children).
The same analysis was performed separately for nine frequent syntactic categories. A significant difference was found only for nouns in phonology. Effects of age and statistical tendencies were found for verbs and determiners in phonology, for determiners and subject preverbal pronouns in syntax.
As well as confirming the importance of phonological difficulties in SLI, our results present a case for a developmental theory of phonological and syntactic deficits in SLI, where differences between SLI and NLD grow with age and where there is a timing difference between phonology (earlier) and syntax (later).