What is underlying problem in SLI? - 4 candidate explanations of SLI (Leonard, 1998): 1. Incomplete grammatical rule systems? immature gram dev (Rice & Wexler, 1975). inability to induce grammar, & hence reliance on rote learning (Crago & Gopnik, 1994). controversial argument is genetic i.e. a specific impairment to Lang Acquisition Device itself 2. Difficulty processing grammatical morphemes? Surface Hyposis (Leonard, 1992) difficulty perceiving & using low salience or low frequency morphemes e.g. box vs. rocks. grammar-specific processing impairment – because of unique difficulty of hearing, processing & linking se low salience, brief bits of info 3. Auditory processing deficit? difficulty w/ processing rapid auditorily-presented info (Tallal & Stark, 1981) i.e. impairment of auditory processing, not specific to lang (‘domain-general’) 4. Generally limited processing ability: Generalised Slowing Hyp (Kail, 1994; Miller et al., 2001). Limited working memory capacity (Garcole & Baddeley, 1993) i.e. general processing impairment
