Verb morphology in Turkish-speaking children with and without DLD: the role of morphophonology

In this study, we examined the verb morphology system of Turkish-speaking preschoolers with developmental language disorder (DLD) and compared their use to that of two groups of typically developing (TD) children. We report data from a total of 80 monolingual children - 40 children with DLD, 20 TD age-matched children and 20 TD younger MLU-matched children. Language samples obtained from the children served as the source of the data. The results show that the children with DLD were less accurate in their use of verb suffixes than both the younger and the age-matched TD children. The most frequent error types included use of bare stems, omission of the suffix, and replacing one finite verb suffix with another. The distinction between witnessed past and reported past also posed a challenge. Multi-level model results showed that phonemic length and irregular morphophonology were the best predictors of the children's level of accuracy. These results indicate that even though Turkish is considered a "verb friendly" language, children with DLD do not succeed in closing the gap with their TD peers. The complex interplay of morphology and phonology in Turkish appears to be the major obstacle for children with DLD acquiring this agglutinative language.