On Grammatical Errors in English SLI Children: A Corpus-based Study Yi-An Lin University of Cambridge 1. Introduction Specific Language Impairment (SLI), also known as developmental dysphasia, refers to a delayed or deviant language development of children in the absence of neurological trauma, cognitive impairment, psycho-emotional disturbance, or motor-articulatory disorders (Eisenbeiss, Bartke, & Clahsen, 2006). Although SLI is a heterogeneous disorder, tense marking has been argued to be a good clinical marker of SLI in English-speaking children (Rice & Wexler, 1996). However, different models have been proposed to explain whether tense-marking errors are syntactical in nature. This paper is also concerned with the nature of grammatical errors made by children with SLI, which involve core syntactic operations such as movement, agreement and case assignment. Therefore, three current accounts of grammatical errors produced by children with SLI, namely, the Agreement and Tense Omission Model, the Agreement Deficit Model, and the Deficit in Computational Grammatical Complexity Model, will be evaluated on the basis of the Leonard corpus in the Child Language Data Exchange System (CHILDES). In the next section, the key claims and predictions made by each model are presented. 2. Literature Review on Three Linguistic Accounts of SLI 2.1 Agreement and Tense Omission Model The Agreement and Tense Omission Model (ATOM) of SLI originates from Wexler’s (1994, 1996) studies on clause structure and inflection in young typically-developing (TD) children. The grammar of TD children can be captured in terms of Wexler’s Optional Infinitive (OI) stage. He claims that TD children undergo a protracted stage during which they alternate between producing finite and infinitive forms of verbs in contexts where finite forms are required in adult grammar. Additionally, TD children at the OI stage tend to omit auxiliaries and copula BE 1 in finite contexts as Wexler observed. Further, Wexler asserts that optional infinitives arise because of the underspecification or omission of the tense feature in the clause representation. Adopting Wexler’s idea, Rice, Wexler and Cleave (1995) propose that children with SLI go through an Extended Optional Infinitives (EOI) stage in which a similar pattern of optional infinitives is found until they are 7 or 8 years of age. Rice and her collaborators propose that the grammar of * This paper is a revised version of the first and sixth chapters of my 2005 master’s dissertation submitted to University of Essex. It was presented at the 2006 Symposium on Research in Child Language Disorders (University of Wisconsin-Madison), the 2006 Child Language Seminar (University of Newcastle upon Tyne), the 2006 Seoul International Conference on Linguistics (Seoul National University) and the Conference on Generative Approaches to Language Acquisition – North America 2 (McGill University). I thank all of the participants for their comments. I am especially grateful to my supervisor, Professor Andrew Radford, for helpful discussion. All errors are mine. 1 In this paper, the capitalised word is the label for various forms of that word. © 2007 Yi-An Lin. Proceedings of the 2nd Conference on Generative Approaches to Language Acquisition North America (GALANA), ed. Alyona Belikova et al., 245-252. Somerville, MA: Cascadilla Proceedings Project.