Object clitic pronouns, definite articles and genitive possessive clitics in Greek preschool children with Specific Language Impairment (SLI): implications for domain-general and domain-specific accounts of SLI

Specific Language Impairment (SLI) is a developmental language disorder in which affected individuals fail to acquire language according to age-expected levels, in spite of typical development in other areas; they have normal non-verbal intelligence and socio-emotional development, no presence of motor speech disorders and no hearing difficulty or evident neurological damage. SLI is present from the earliest stages of development, in preschool children, and may continue on into adolescence and adult life. Current investigations focus on pinpointing the clinical features of SLI across languages and on exploring its underlying nature and causes. A central theoretical debate on SLI concerns what type of account can best explain the morphsyntactic deficits observed; on one hand, researchers in favour of domain-specific accounts argue that SLI is the result of a selective limitation in the language system (e.g. van der Lely 2003). In contrast, the proponents of domain-general accounts argue that the language deficits in SLI are caused by deficits in general cognitive processing mechanisms, affecting other areas of cognition as well as language (Leonard 1998). Crosslinguistic investigations in languages with different morphosyntactic properties are crucial in putting the predictions of these frameworks to the test. With regards to the clinical characteristics of SLI, there is converging evidence that children with SLI have significant limitations with the acquisition of morphosyntax (Bishop 1997; Leonard 1998). These difficulties are critically dependent on the language studied. Thus, in English and German, deficits in verbal morphology have been highlighted as a core feature, specifically consisting of omissions of the past tense morpheme (-ed) for English, and subject-verb agreement inflections (e.g. third person inflection –s, auxiliary and copula be) for English and German (Clahsen 1989; Rice, Wexler & Cleave 1995). In Romance languages such as Italian and French, third person object clitic pronouns are highly omitted by children with SLI (Bortolini, Caselli, Deevy & Leonard 2002; Jakubowicz, Nash, Rigaut & Gerard 1998; Paradis, Crago & Genesee 2005). Definite articles have also been pointed out as an area of difficulty for Italian-speaking children with SLI (Bottari, Cipriani, Chilosi & Pfanner 1998). In Greek, similarly to Romance languages, there is evidence that third person object clitic pronouns (in accusative case) and definite articles pose significant difficulties for preschool children with SLI (Tsimpli & Stavrakaki 1999; Tsimpli 2001). In this paper we aim to contribute to the ongoing investigation on the characteristics and etiology of SLI by (a) identifying certain morphosyntactic structures that are particularly difficult for Greek-speaking preschool children with SLI, with emphasis on object clitic pronouns, definite articles and genitive possessive clitics and, (b) by exploring the theoretical implications of the findings for accounts of SLI. In the next section we will outline the properties of the target structures in Greek, and will review findings from Greek studies of SLI. We will then highlight accounts that could explain the pattern of deficits and will present the current study.