Dyslexia: teaching to strengths and weaknesses
Terezinha Nunes

Terezinha Nunes, department of psychology, Oxford Brookes University, outlines the findings of research, made possible by a grant from the Medical Research Council, on what is best for dyslexic children: teaching to their strengths or overcoming weaknesses.

Strengths and weaknesses of dyslexic children before school
The evidence on causes of dyslexia leaves little doubt that children who have major difficulties with phonological awareness tasks are at risk of developing reading problems. Children who later become poor readers perform pooriy in measures of phonological awareness at schools entry: for example, they have greater difficulties in identifying which two words out of three rhyme with each other and also which two words out of three have the same initial sound. They continue to perform poorly in measures of phonological awareness throughout primary school, even if they are compared not with their age cohorts but with younger children who have the same reading age (Bryant & Bradley, 1983; Goswami & Bryant, 1990).  Furthermore, children of dyslexic parents, who show higher incidence of dyslexia than children of normal readers, will have a decreased risk of dyslexia if they receive phonological awareness instruction in kindergarten (Petersen & Elbro, 1999).

However, this does not mean that children who later become poor readers are generally backwards in linguistic skills. Words can be analysed into their constituent sounds or, alternatively, into their constituent morphemes, which are units of meaning. For example, the word 'cats' has four sounds, each represented by one letter; if analysed into morphemes, it contains two morphernes, 'cat' (which designates a particular type of animal) and 's' (which ndicates that there is more than one cat, and thus represents the plural). Children who later become poor readers are not found to be consistently worse at tasks of morphological awareness than their age cohorts when they enter school (Bryant, Nunes & Bindman, 1998) nor are they behind children of the same reading age later on in school in morphological skills (Carlisle, 1987). This difference between dyslexic children's awareness of phonology and of morphology suggests that they have both strengths and weaknesses in their linguistic skills.

The development of word reading and spelling in dyslexic children
Not all words in English orthography can be analysed through simple letter-sound correspondences. Some words involve what are called phonological conditional rules because they can be expressed as 'if rules'. For example, the letter 'c' is read like /k/ if followed by a consonant or the vowels 'a', 'o' or 'u' but it reads like /s/ if followed by 'e', 'i' or 'y'. Conditional rules also apply 'at a distance': the final 'e' rule is an example which operates by marking the difference in the vowels in word pairs such 'hat-hate', 'hop-hope' and 'pin-pine'. Poor readers who have mastered simple letter-sound correspondences have significantly more difficulty with these phonological conditional rules than younger, normal readers of the same reading age (Nunes & Aidinis, 1999).

Other words involve morphological rules. To take a simple example, we spell 'magician' with a 'c' because the stem 'magic' ends with 'c', but the letter 'c' is not usually what we would use to represent the sound it represents in 'magician'. Here a good phonological analysis is certain to produce a spelling error. We use 'ian' at the end because this is a suffix that forms person nouns, as in musician, physician and ltalian. College students with a history of reading difficulties in primary school do not have more difficulty in spelling this type of words than other college students, although they still have more difficulty in spelling words that involve phonological conditional rules (Bruck, 1993).

The pattern of stengths and difficulties observed before children enter school is replicated in the poor readers' spelling development. So we asked the question, when working with older dyslexic children who have mastered simple letter-sound correspondences, is it possible to teach them to analyse words into morphemes rather than phonemes, basing their reading and spelling instruction on their strengths rather than their difficulties?

An intervention study with dyslexic children
Our aim in this study was to test the effectiveness of two training programmes for dyslexic children, both of which aimed at developing their word reading and spelling beyond the initial stages. One training programme concentrated on pholology and included practice in phonological analysis as well as teaching conditional phonological rules. The second programme focused on teaching morphology, including practice in analysing words into morphemes and using morphemes to read and write long words. The effectivenes of the programmes was assessed by means of comparison with a control group.

We identified 59 children in 12 schools in Oxford and London whose average reading and spelling age was at least 18 months behind their chronological age. Their mean age was between 8.5 and 12 years. Of these, 55 children met a criterion in a spelling test that indicated that they had learned basic letter-sound correspondences and were included in the study. All the children had normal IQ.  They were then assigned randomly to one of the three groups - phonological intervention, morphological intervention and control - with the restriction that each group would be represented in each school. To extend the benefits of the intervention to as many children as possible, fewer children were assigned to the control group than to the treatment groups. The final number of participants by group was: 19 children in the phonological intervention group, 21 in the morphological intervention group, and 15 in the control group.

All the children were tested twice within an interval of about seven months. The first assessment took place before the training and the second after the training for the children participating in the training programmes. We wanted to know whether during this interval they made more significant progress than the control children, who were receiving only their normal school instruction during this time.

Using a standardised reading test, the WORD (Rust, Golombock & Trickey, 1993), we observed that the reading age of the children in the control group increased by about 6.5 months during this time. The reading age of the children in the phonological training programme increased by 13.1 months and that of the children in the morphological training group increased by 11.7 months. The difference between the children in the phonological training group and the control group was statistically significant but the progress of the children who received morphological training did not differ significantly from the progress of the children in the control group. This suggests that using a type of training that is based on the children's strengths in morphological analysis cannot compensate for their difficulties with phonological analysis. Teaching them to overcome these difficulties was a more effective way to promote their progress in reading.

The same pattern of results was observed when we asked the children to read pseudowords. Pseudowords are sequences of sounds that can be pronounced and written as if they were real words but they happen not to be (e.g., kished, dut). Pseudowords are used in research because they can eliminate the possibility that a group of children might perform better in a reading assessment because by chance they practised many of the words contained in a test: for example, they might have been reading a book that happened to have the test words. In this study, the children in the phonological training programme progressed significantly more in reading pseudowords than the children in the control group; the children in the morphological training programmed did not.

Two other assessments were used to investigate the children's progress, one related to phonological conditional rules and the second to morphological rules. As expected, the children in the phonological programme made significantly more progress in reading words and pseudowords with phonological conditional rules than those in the control group; the children in the morphological programme did not. No significant differences were observed in spelling similar words and pseudowords. Our training programme had a specific effect on these advanced phonological rules in reading but not in spelling.

In the assessments involving morphological rules, the children in the morphological programme made significantly more progress in spelling than those in the control group but the children in the phonological programme did not. The groups did not differ in the amount of progress they made in reading the same type of words. Thus our morphological programme had a specific effect on spelling but not on reading.

Conclusion
We conclude that it is necessary to try to help dyslexic children overcome their weakness in phonological awareness and that teaching to their morphological strengths does not compensate for their weakness. However, a phonological programme does not suffice as there are English words whose spelling is not based on phonological but on morphological rules. Only the children in the morphological programme made significantly more progress in spelling these words. Thus reading and spelling instruction for dyslexic children must work with their strengths and weaknesses in distinct ways.
 

References
M. Bruck (1993) Component spelling skills of college students with childhood diagnoses of dyslexia, Learning Disabilities Quarterly, vol. 16, 171-184.
P. Bryant & L. Bradley (1983) Children's reading problems, Oxford: Blackwell.
P. Bryant, T. Nunes & M. Bindman (1998) Awareness of language in children who have reading difficulties: Historical comparisons in a longitudinal study, Journal of Child Psychology and Psychiatry, vol. 39, 501-510.
J. Carlisle (1987) The use of morphological knowledge in spelling derived forms by learning-disabled and normal students, Annals of Dyslexia, vol. 37, 90-108.
U. Goswami & P.Bryant (1990) Phonological skills and learning to read, Hove (Sussex): Lawrence Erlbaum.
T. Nunes & A. Aidinis (1999) A closer look at the spelling of children with reading problems, in T. Nunes (Eds.) Learning to read: An integrated view from research and practice, Dordrecht: Kluwer Academic publishers.
D. K. Petersen & C. Elbro (1999) Pre-school prediction and prevention of dyslexia: A longitudinal study with children of dyslexic parents, in T. Nunes (Eds.) Learning to read: An integrated view from research and practice, Dordrecht: Kluwer Academic publishers.
J. Rust, S. Golombock & J. Trickey (1993) WORD. Wechler Objective Reading Dimension, London: The Psychological Corporation.

Research team:
Tereziriha Nunes, Department of Psychology, Oxford Brookes University
Peter Bryant, Department of Psycholody, Oxford University
Ursula Pretzlik, Departmentof Psychology, Oxford Brookes University
Jane Hurry, Institute of Education, University of London  

Subscribe to Literacy Today