motor impairment and language

[Bencie Woll]

We would like to respond to the recent correspondence from Jordan
Zlatev and Brian MacWhinney relating to the relationship (if any)
between language development and sensorimotor experience. In a paper
presented at the Boston Child Language Seminar in 1997 and published
in the proceedings* we report on a study of 10 severely motor-impaired
children with Spinal Muscular Atrophy aged 18-35 months. These
children are confined to wheelchairs, unable to stand independently or
ambulate, but have normal cortical functions. Using the MacArthur CDI
we found average levels of vocabulary (with slightly below-average
levels in the youngest subjects due to deficits in items related to
mobility) but significant advancement in morphological development,
with 8/10 at or above the 75th percentile, and 6/10 above the 90th
percentile in over-regularisations. These scores are up to 10 times
those of normal children.

On this evidence, neither the Piagetian perspective (as Monod phrases
it): that a paraplegic child would have difficulties in developing
language; nor Chomsky's prediction: that there is no or only a
marginal relationship between language and motor development, is
supported. Our findings suggest instead that the inability of children
with SMA to explore objects and forms in the environment may advance
the analysis of patterning in language, independently of vocabulary.
These children examine language in place of a world they cannot reach,
practising the way words are formed while able-bodied toddlers are
engaged in motor and spatial learning.

We propose two mutually compatible explanations: 1) different objects
of learning in early childhood are in competition and language can
advance if the child is less engaged in motor and spatial learning; 2)
 the mechanisms of procedural learning, identified as fundamental for
motor and behavioural skills arising from direct actions and
experiences, are also implicated in the development of the
morphological rule system.

Further studies are being undertaken to explore syntactic, pragmatic,
and other aspects of these children's language development.

*Sieratzki JS & Woll B (1998) Toddling into language: precocious
language development in motor-impaired children with spinal muscular
atrophy. In A Greenhill, M Hughes, H Littlefield & H Walsh (eds.)
Proceedings of the 22nd annual Boston University Conference on
Language Development, Vol. 2. Somerville MA: Cascadilla Press. pp.
684-94 (a revised version will be submitted shortly for journal
publication)

As well as the paper in the Proceedings, an informal version may be
read on the Jennifer Trust for Spinal Muscular Atrophy website
<http://www.jtsma.demon.co.uk>

Harry Sieratzki & Bencie Woll

Professor Bencie Woll
Chair of Sign Language and Deaf Studies
C.C.S.
City University
Northampton Square
London EC1V 0HB

Tel: +44 171 477 8354
Minicom/TTY: +44 171 477 8314
Fax: +44 171 477 8577
e-mail: b.woll at city.ac.uk