Tense and Agreement in Greek SLI: A Case Study

Specific Language Impairment (SLI) is a developmental language disorder characterised by morpho-syntactic errors in the absence of neurological trauma, cognitive impairment, psycho-emotional disturbance, or motor-articulatory disorders. Among the hypotheses that have argued for SLI as an impairment at the linguistic level, rather than at the cognitive or perceptual level, there is a debate as to whether SLI is primarily an impairment in the marking of tense features, agreement features, or both. The current study uses data from spontaneous speech of a Greek SLI child to examine whether, in a language with rich agreement and tense marking, we can find evidence supporting one of these competing hypotheses. The subject was a monolingual Greek speaker aged 5;5, within the normal range of IQ, independently diagnosed as SLI, and receiving language therapy at the time of data collection. We investigated the subject’s use of verb forms for both accuracy in obligatory contexts and accuracy of forms. We present the findings for the subject’s performance and focus on error analyses to argue that this SLI subject is impaired in subject-verb agreement marking, whereas tense marking is unimpaired. These results, we argue, support the view that SLI selectively affects the morpho-syntactic features involved in agreement operations.