ABSTRACT
Causal explanations for the morphological vulnerability observed in specific language impairment (SLI) have attributed the problem to (a) the lack of phonological salience of morphological inflections (Leonard, 1988, 1989), to (b) differential typologies of languages with sparse and complex morphology (Dromi, Leonard, & Shteiman, 1993; Leonard, Bortolini, Caselli, McGregor, & Sabbadini, 1992; Lindner & Johnston, 1992), as well as to (c) various deficiencies in the underlying grammar, including a featureless grammar (Gopnik 1990a, 1990b) and an impairment in rule construction (Gopnik, in press-a, in press-b), (d) the extended use of infinitives for inflected forms (Rice, 1993, 1994; Rice & Wexler, 1993), and to (e) problems in agreement checking relationships that differentially affect agreement across the grammar (Rice, 1993, 1994).
