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

R. INGHAM
cognitive deficits. They show a range of problems with language including
varying combinations of grammatical, phonological, and lexical semantic
deficits. One leading characteristic of this population is a much-documented
difficulty in forming regular past tense, among other problems of course.
Proposals by Gopnik & Crago (1991) and Rice, Wexler & Cleave (1995) have
argued for a selective deficit in grammatical morphology, and thus support a
modular approach. On the other hand, Marchman, Wulfeck & Ellis Weismer
(1999) explore a non-modular approach to past tense impairment, arguing
against the dual mechanism theory. They suggest that protracted lexical
learning which they say is characteristic of SLI may be responsible for SLI
children’s errors with past tense. Bates & Goodman (1997) also appear to
claim that no dissociation between grammatical ability and lexical ability in
such children should be in evidence in children with SLI.
Locke (1994, 1997) also related grammatical and lexical development,
but not in the same way. The second phase of his analysis of child language
development, which Locke considers to be accomplished by right hemisphere
neural resources, is dedicated to ‘collecting utterances’ as Locke expresses it.
This period is one in which the child uses language as single words or fixed
expressions without showing evidence of having analysed input so as to
achieve grammatical representations. In the third phase the child discovers the
regularities in language, especially in grammar, as evidenced by
overregularisation phenomena. This phase is largely a matter of left
hemisphere neural resources.
In language impairment, what happens, according to Locke, is that the
child experiences problems in phase 2, having utterance processing
limitations which results in insufficient stimulation of the neural resources
available in phase 3. The analytical mechanisms in stage 3 require a
substantial amount of stored utterances on which to work, otherwise it will
not properly succeed in extracting the patterns of the target language.
Crucially this does not cause the child’s ability to learn language to crash
completely. Instead the child deploys other brain capacities to address the task
of learning language.
The idea put forward by Locke is that children with SLI need not be
lacking in the species-specific grammatical analysis capacity argued for by
Principles & Parameters theory, but rather in the prerequisite for that capacity
to operate - the capacity to acquire ‘utterance material’. It would appear that
the capacity to acquire utterance material is essentially what acquisitionists
have studied under the heading of early lexical acquisition, that is, the
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