Sibling resemblance for specific components of linguistic competence in families of speech/language impaired children

Abstract

We examined performance on specific linguistic tests in 23 English and French speaking families, recruited from clinical and other sources, of children who met the following criteria for specific language impairment (SLI): clinically diagnosed language impairment without peripheral hearing loss, mental retardation (non-verbal IQ≥70), neurological disorder, schizophrenia or autism. Subjects, at least 9 years old, completed a battery of French or English language tests, including derivational morphology, verb tense morphology, grammaticality judgement, syntactic comprehension, and pointing. listening comprehension and WUG pluralization test were analyzed only in the English group. The verb tense morphology (real words) and verb tense morphology (non-real words), respectively, showed non-parametric sibling correlations of 0.39 and 0.35 ( p<0.05, two-tailed) in 38 pairs (mixed gender) from ten French test pedigrees. In the English group, derivational morphology showed significant 0.52 correlation in 41 sibling pairs from the densely affected FE pedigree. After controlling for age, sibling correlation for verb tense morphology (real words) remained significant, and derivational morphology correlation in the FE pedigree was borderline ( p=0.05). Impaired grammatical morphology is a predominant aspect of SLI, and the present study, which requires independent replication, suggests that verb tense morphology and derivational morphology warrant particular attention in future familial and genetic studies.