Reading Working Papers in Linguistics 4 (2000) - The University of ...

LEXICAL AND GRAMMATICAL DEFICITS IN SLI
investigating a group of children with SLI who appear to have quite severe
problems in both expressive and receptive lexical abilities.
Members of these two groups were matched individually with LN
children to the nearest 3 months at a maximum on BPVS a.e. scores (most
subjects to within 1 month).
The [+LD] group had a BPVS a.e. score of two years or more below
their CA. If the position taken by Locke (1994, 1997) is correct, that is if we
assume that these children had been experiencing a constant lag in lexical
development, this group should have experienced fairly severe lexical storage
difficulty, leading to grammatical impairment. Their performance on
grammatical measures should therefore be well below that of their LN BPVS
matches.
The [-LD] group had chronological age-equivalent lexical abilities as
measured by BPVS. If the position taken by Locke (1994, 1997) is correct,
this group should not have experienced the difficulty with storing lexical
material that leads to grammatical impairment. Their grammatical
performance should therefore approximate to that of LN BPVS matches.
The hypothesis to be investigated was that only children with SLI with
a lexical deficit, i.e. the SLI [+LD] group, should show an associated deficit
in grammatical forms. The grammatical measures selected were among those
most studied in the literature on SLI: finiteness marking on verbs, and aspects
of grammar related to it, i.e. null subjects and incorrect case on subject
pronouns. These have been taken as key indicators of grammatical deficit by
investigators such as Rice, Wexler & Cleave (1995) and Loeb & Leonard
(1991).
In addition, the profile of SLI children’s morphosyntax was extended to
include possible deficits with argument structure (a-structure) realisation (cf.
Pinker 1989). Loeb, Pye, Richardson & Raymond (1998) report finding no
significant differences between children with SLI and chronological and
language matched controls in the production of argument structure
alternations. However, Schelletter et al. (1996) found an association between
argument structure realisation in children with SLI and morphological deficit.
SLI children with a morphological deficit were poor at argument structure
alternations– they typically produced only one alternant where the verb
offered two. For example, they made use solely of a transitive structure, or
solely an intransitive structure, to describe scenes providing a context for a
given alternating verb, but which differed only in that one depicted an agent
and the other did not. Those with no morphological deficit were nearly as
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