Developmental language disorder: similarities and differences between 6-year-old mono- and multilingual children.

This study investigated language ability in 6-year-old mono- and multilingual children who, at age 2;6 years, had screened positive for developmental language disorder (DLD). One hundred children (32 girls, 68 boys) were assessed at an average age of 2;9 years (T1) and 85 of them (30 girls, 55 boys) were reassessed at age 6;0 years (T2) using a standardised test battery. Of these, 68 (23 girls, 45 boys) met the criteria for DLD diagnosis; 28 of them were monolingual and 40 multilingual. Language profiles at T2 were analysed, as were the associations between DLD and a mono- or multilingual background as well as other measures collected at T1, including mean length of utterance (MLU), heredity and parental education. As expected, the results showed that the total group (including both mono- and multilingual children) scored below test norms for 6-year-olds on all language tests, except for receptive vocabulary, where the monolingual children scored in line with those norms. The multilingual group performed significantly less well than the monolingual one on language comprehension, receptive vocabulary, recalling sentences, word finding and story retelling; disparities regarding MLU and language comprehension were already evident at T1. Interestingly, MLU at T1 showed a moderate association with language comprehension at T2 in the total group. The monolingual children were more likely than the multilinguals to have heredity for DLD or reading and writing disorders. In conclusion, language difficulties identified through screening and assessment before age 3 years often persist at age 6 years.