01 NRDC Dyslexia 1-88 update - Texthelp

48
Research Report
Are there any impediments to the acquisition of phonemic awareness?
The most critical consideration for adult learners is whether age itself is an impediment to
the acquisition of phonemic awareness. However, since a small-scale experimental study has
shown that neurologically normal illiterate adults may display rapid improvements in
performance when explicit instruction and continuous corrective feedback are provided in a
phoneme deletion task, it appears that maturity should not impede the acquisition of this skill
(Morais et al., 1988). Neither does it appear to do so: in an intensive adult literacy programme
in Turkey (where the orthography is transparent), ‘neoliterates’ have been reported to show
significant improvement in letter and word recognition, phonological awareness and spelling
levels (Durgunoglu & Öney, 2002). Similarly, among adults who have previously learned to
read in a nonalphabetic script, specific instruction in phoneme deletion has led to
improvements not only in phonemic analysis but also in word reading in an additional,
alphabetic language (Cheung, 1999).
These findings may be valid for people with normal speech perception, but are they valid for
people whose speech perception is now impaired or was impaired when they were first
learning to read and write? Moreover, are the findings valid for people whose perception is
unimpaired but for whom the phonetic or acoustic features of the language most familiar to
them at a critical period in their development were different from those of the language they
now seek to read and spell? It appears that the findings may not be valid in two distinct
circumstances.
The first of these circumstances concerns hearing ability. Generally speaking, a perceptual
impairment early in life may be sufficient to cause a phonological disorder which persists
even after the perceptual impairment has resolved (Bird & Bishop, 1992). Children with mildto-moderate
sensorineural hearing loss are as impaired as normally-hearing children with
specific language impairment on tests of phonological discrimination (Briscoe et al., 2001).
Children who have otitis media with effusion (‘glue ear’) may have difficulty in making fine
discriminations between speech sounds (Singleton et al., 2000), although the otitis media may
need to be both chronic (Nittrouer, 1996) and bilateral (Stewart & Silva, 1996) for speech
perception and articulation to be compromised, with effects that may then persist into midadolescence
(Bennett et al., 2001), long after the hearing problem itself has cleared up. In this
case, the impairment can be described as having a biological origin.
However, in the case of pre-school children, any linguistic difficulties attributable to otitis
media may be outweighed by the difficulties associated with social disadvantage (Paradise et
al., 2000; Vernon-Feagans et al., 2002; Wallace et al., 1996), when language development may
be impaired irrespective of hearing difficulty (Tough, 1977; Walker et al., 1994).
The second circumstance concerns the phonetic or acoustic features of language in
childhood. From a connectionist perspective (see above, p.36), it has been suggested that
speech perception involves the integration of multiple acoustic properties, so that learning
how best to weight these properties may then be prerequisite for recognising phonetic
structure (Nittrouer, 1996). Individual perceptual weighting strategies have been found to
differ not only according to the quality of perception but also according to the quality of the
signal (Nittrouer, 1996). In the latter case, learners from disadvantaged backgrounds—where
language may be suboptimal in both quality and quantity—have been found to perform even
less well on phonemic awareness tasks than learners with chronic otitis media (Nittrouer,
1996). Nevertheless, disadvantaged learners with speech segmentation deficits may respond
well to alphabetic instruction (Duncan & Seymour, 2000). In the case of such learners, who