Subject Case in Children With SLI and Unaffected Controls: Evidence for the Agr/Tns Omission Model

Kenneth Wexler, Carson T. Schütze, Mabel Rice
1998 Language Acquisition  
Running head: Subject case and Agr/Tns Omission PURPOSE Specific Language Impairment (SLI) is a linguistic deficit in young children who do not have a corresponding "cognitive" deficit. There is a substantial body of evidence that argues that children with SLI have grammars that are complex, highly integrated computational systems, of essentially the same sort that unaffected children and adults have. On this view, the deficit in SLI is that particular features of this highly integrated system
more » ... re lacking, or develop late (Wexler (1996) , Rice, Wexler, and Cleave (1995), Rice and Wexler (1996b)). The purpose of this paper is to present evidence for this view from an array of phenomena involving the notion of morphological case, a reflex of structural relations in the grammatical system. We will show that some complex interactions between case and verbal inflection are at work in the computational systems of English-speaking children with SLI. Thus, this investigation will provide further evidence that children with SLI have grammars that are governed by principles that also govern non-deviant linguistic systems. It is important to be clear about what the empirical domain of concern is. Much recent work in morphosyntax has converged on the conclusion that there are two distinct grammatical systems with different properties, each of which often goes by the name "case." (See Schütze (1997) for review and discussion.) One of these, "abstract Case" or "structural licensing," determines the positions where noun phrases can appear in a sentence and forces A-movement, for instance in passives; we will not be concerned with this system here. The other system, "morphological case" (hereafter simply "case"), is responsible for featural distinctions among noun phrases that may be reflected in overt morphological inflections (e.g., the distinctions among Nominative (NOM), Accusative (ACC) and Genitive (GEN) forms of pronouns in English, and nouns in other languages). We assume that the two systems are largely independent, such that a child may have an adult-like structural licensing system but an apparently non-adultlike morphological case system. Nonetheless, we assume that morphological case markings arise from structural
doi:10.1207/s15327817la0702-4_8 fatcat:ugk2qtr3sbfujnjdyua3d6buri