Linguistic abilities in developmental dyslexia: A cross-linguistic approach

Maria MengisidouInstitute of Education, University of London

Wednesday 5th November, 2014

“Reading is the most important portal to knowledge in our information age, from books to blackboards to the Internet”

(Gabrieli, 2009, p280)

“Fifty ways to fail reading acquisition”(Ramus, 2004, p817)

Biological causes

Sensory problemsIntellectual disabilityLanguage problemsAttention problemsBehavioural problems

Behavioural causes

Social problemsFamily problemsPedagogical problems

Developmental dyslexia

After excluding all these obvious causes of failure

3-6% of school-age children have specific and unexpected difficulties to learn to read

According to the International Classification of Diseases (ICD-10), developmental dyslexia (under the name of specific reading disorder) is a specific and significant impairment in the development of reading skills that is not solely accounted for by mental age, visual acuity problems, or inadequate schooling (World Health Organization, 2011)

How is an unknown word read?

Alphabetic system (i.e., letters and sounds)

Decoding

– The mapping of visual symbols onto phonological formse.g., C A T . . . /K/ /AE/ /T/

Reading development therefore depends upon the phonology of language

With an important environmental influence on reading development being the language in which a child learns (Harris & Hatano, 2000)

The Greek languageSpelling consistency

– In most cases, a single letter can be pronounced in the same way, for example the letter ‘α’ (alpha) in the sentence,

“Αυτά τα κορίτσια φύτεψαν όλα τα λουλούδια”

– However, in the English language a single letter can be pronounced multiple ways, for example the letter ‘a’ in the sentence,

“She was carefully planting all the cabbages around the many potatoes” (Thomson, 2010)

In typical development results in...

Faster development of decoding skills in reading in shallow compared to deep orthographies (Seymour, Aro, & Erskine, 2003)

In developmental dyslexia results in...

The reading symptoms of dyslexia varying across orthographies; In languages such as Greek or Italian, reading difficulties are identified by slow phonological decoding (few reading errors occur), whereas in English poor reading accuracy is the primary behavioural marker (Landerl, Wimmer, & Frith, 1997)

Children with phonological impairments being at risk of reading difficulties in all languages

The phonological deficit hypothesis, 1

Cognitive level

One and single cognitive deficit, the phonological deficit, accounts for dyslexia

The phonological deficit in dyslexia originates from degraded or less well specified phonological representations (i.e., the mental representations of the basic sounds of speech, the phonemes)

The phonological deficit hypothesis, 2

Phonological awareness tasks– ταν . . . ταν . . . αν

– τοκαλι . . . τοκαλι . . . καλι

Phonological short-term memory tasks (STM)– 3, 7, 9 4, 5, 6, 3 8, 6, 2, 1, 9

– μουκολα, σαντουρλι, μαντουρλανοτι

Rapid automatic naming (RAN)– A K G H D F P R L Ν Μ W X Ε

– 1 4 6 8 9 4 2 6 9 7 2 1 4 8 6 2

The phonological deficit hypothesis, 3

For older children who can read, phonological impairment is most evident when asked to read aloud non-words (i.e., nonsense), such as “jound” that are unknown and can only be pronounced or decoded on the basis of grapheme-to-phoneme mapping principles

Examples of Greek non-words: δαλές, σαποτέ, φαλίκε, κριπήτα,μπεσίκο, τεπό, ναμής, ξεσμονή, αγκρηνός, etc.

The present studyRationale

There has been concern over whether the findings of studies in monolinguals can be applied to children who grow up speaking two languages called bilinguals

Contradictory evidence for an association between bilingualism and language-related problems

Some positive cognitive effects of bilingualism on literacy development have also been reported (e.g., higher levels of phonological awareness in bilingual children compared to monolingual children)

The present studyAims

a) To investigate whether a bilingual Greek-English child with dyslexia diagnosed as having dyslexia in the English language presents deficient decoding skills also in the Greek language

It was predicted that the child with dyslexia would show accurate but slow decoding skills in Greek compared with bilingual controls

b) To investigate the relationship between decoding and phonological skills among the bilingual controls

It was expected an association between decoding and phonological skills in the control group

The present studyAims

c) To examine the phonological skills of the bilingual child with dyslexia by comparing them to those of the bilingual controls

It was expected that the child with dyslexia will show adequate performance in manipulating phonological speech sounds (i.e., phonological awareness tasks); however, evidence of phonological impairments, either in the speed of accessing (i.e., RAN tasks) or in the capacity of holding (i.e., phonological STM tasks) phonological representations was also expected

The present studyMethod

Sample● Greek schools in London, UK

● A 10-year-old bilingual girl with dyslexia

● 26 bilingual children with typical development [mean age 11 years 5

months (SD = 2.45, min = 9;0, max = 18;1); 14 boys and 12 girls]

Ethical approval (IOE)

Letter of consent plus Parents’/Teacher’s written consent

Part-time schools (usually function twice a week between 18:00-20:00 duringweekdays, and 10:00-13:00 or 14:00-17:00 on Saturday); One full-time school inWest London

The present studyTasks

Task of reading 19 nonwords Test of Reading Performance (TORP), adaptation in Greek by Padeliadu &

Sideridis (2000)

Tasks of phonological skills Evaluation de la Lecture (EVALEC), adaptation in Greek by Talli (2010)

Helenic version of WISC III, standardisation in Greek by Georgas, Paraskevopoulos, Bezevegis, & Giannitsas (1997)

The present studyTasks

Syllable awareness

- Syllable deletion (e.g., tokali . . . kali)

Phonemic awareness

- Phoneme deletion CVC & CCV (e.g., zin . . . in & pra . . . a, respectively)

Phonological short-term memory (STM)

- Nonword repetition & Digin span (e.g., bartino & 3-8-6, respectively)

Rapid automatic naming (RAN)

- Colours & Pictures (e.g., green, blue & table, door, respectively)

ResultsNon-word reading

Controls DYS

0

10

20

30

40

50

60

70

80

Non-word reading accuracy Non-word reading speed

ResultsSyllable awareness

Controls DYS

0

5

10

15

20

25

30

35

40

Syllable deletion accuracy Syllable deletion speed

ResultsPhonemic awareness

Controls DYS

0

5

10

15

20

25

30

35

40

Phoneme deletion CVC accuracy Phoneme deletion CVC speed

Phoneme deletion CCV accuracy Phoneme deletion CCV speed

ResultsPhonological STM

Controls DYS

0

10

20

30

40

50

60

70

80

90

Non-word repetition accuracy Non-word repetition speed Digit span

ResultsRAN

0

20

40

60

80

100

120

140

Controls DYS

RAN-colours accuracy RAN-colours speed RAN-pictures accuracy RAN-pictures speed

Variable Control group

Syllable deletion accuracy .49

Syllable deletion speed -.56

Phoneme deletion CCV speed -.52

RAN-colours accuracy .50

RAN-colours speed -.53

Results, 5Correlations between non-word reading & phonological skills

Discussion, 1

Poor non-word reading ability

Difficulty in manipulating with accuracy phonemes of phonologically complex non-words (i.e., trisyllable or with CCV syllable structure); however, no difficulty in doing so with phonemes of monosyllable non-words with simple (CVC) syllable structure

Substantial difficulties in tasks tapping access, rapid (i.e., RAN) or not (i.e., phonological STM), in phonological representations

In typically developing children non-word reading appears to be associated with phonological skills

Discussion, 2

The present findings support previous findings of:

a) Decoding difficulties being present in children with dyslexia

b) Decoding skills being associated with phonological skills among typically developing readers

Finally, the findings could be explained on the basis that the difficulty of the child with dyslexia in phonological tasks can originate from an access difficulty in phonological representations due to load of short-term memory, and not that much due to deficient phonological representations (trisyllable nonwords > monosyllable nonwords

To all children, parents, teachers and schools who supported our study

Chloë Marshall, Institute of Education, University of London

Stavroula Stavrakaki, Aristotle University of Thessaloniki

Ioanna Talli, Université Paris Descartes & Aristotle University of Thessaloniki

Thank you!