When does phonological impairment cause literacy problems?

1. When does phonological impairment cause literacy problems? Dorothy Bishop Experimental Psychology University of Oxford Powerpoint and references will be on my website

2. What we have learned today • Phonology is not a single skill • Segmental vs. higher-level structure • Input vs. output • Perception vs. memory • Hard to disentangle, but people are devising wonderfully ingenious tasks

3. Why is phonology important in reading? • Two ways to learn to read a word • If word is totally unfamiliar: decode letters into sounds to achieve pronunciation CAMEL /k/+/a/+/m/+/e/+/l/ /'kaml/ /kamel/

4. Phonological skills involved in decoding • Knowledge of mappings from letters to sounds • Distinct representations of phonemes • Ability to segment syllables into phonemes • Combine sequence of sounds into syllables • Match assembled string to a similar lexical entry • Learn to do this rapidly with larger orthographic units

5. lexical representation Why is phonology important in reading? • Another way to learn to read a word • Incorporate orthographic information in lexical representation of a known word /kaml/

6. /'kaml/ CAMEL lexical representation Why is phonology important in reading? • Another way to learn to read a word • Incorporate orthographic information in lexical representation of a known word Does not require phonological analysis

7. Reading without decoding • Patient PS, L hem. infarct aged late 40s • Phonemic errors on reading aloud and spontaneous speech • Excellent comprehension of written words; can judge synonyms, define words, match to pictures • Homophones: can only relate to correct meaning, i.e. cannot respond “inherits” to word “air” • Nonwords: very poor at reading Hanley, J. R., & Mcdonnell, V. (1997). Are reading and spelling phonologically mediated? Evidence from a patient with a speech production impairment. Cognitive Neuropsychology, 14, 3-33.

8. Syntax Today’s talk raise questions about causation Phonological skill Literacy

9. What has not been discussed Phonological skill Literacy

10. Phonological deficits in dyslexia: a symptom rather than a cause? Evidence from: • Orthographic influences on phonological tasks • Phonological processing in non-literate people • Phonological skills as predictors of literacy • Literacy in children with sensory or motor conditions affecting phonology

11. 1. Orthographic influences on phonological tasks

12. Orthographic influences on phonological judgement Judging whether pictures have rhyming names; Children more accurate if can use orthography Bishop et al, 1989

13. Orthographic influences on phonological judgement Phoneme awareness: task performance affected by orthography Castles et al, 2003 • Tasks where orthography no help (or may hinder) • e.g., take the 'w' from squabble • cf. transparent condition • e.g., take the 'r' from struggle • Also phoneme reversal: gnat vs mood.

14. 2. Phonological processing in non-literate people

15. Phonological processing in non-literate people • “Illiterates, who lack the linguistic construct ‘phoneme’, cannot perform oral tasks that require the awareness of that construct” • Tarone & Bigelow, 2005, p 82 • Seminal study by Morais et al (1979): Non-literate Portuguese worse than Belgian first-graders at tasks of phoneme deletion/addition; those with some literacy attainments did better

16. Do not differ on Rhyme judgement Phoneme discrimination Word repetition Nonword repetition (short) Categorical perception* Do differ on Phoneme deletion Phonological fluency Nonword repetition (long) Comparison of literate vs. nonliterate adults: summary * but less precise categorical boundary; Serniclaes et al, 2005 See also Kosmidis et al, 2004; Castro-Caldas et al, 1998; de Santos Loureiro et al, 2004

17. 3. Early phonology measures as predictors of later reading

18. Early phonology measures as predictors of later reading • Bradley and Bryant (1985); famous demonstration that preschool phonological awareness accounted for significant variation in reading outcome after allowing for IQ, vocabulary. BUT! • “...the sound categorization tests that we gave to the 4-year-old children were really rather good at picking up those children who would eventually become good readers. The percentage success .. ranged from 40 to 53%. On the other hand, these same tests were very weak indeed at predicting reading failure. The successful rate of prediction of poor readers ranged from as low as 14% to 28%.” • Bradley & Bryant, p. 105

19. Wimmer et al, 1991 • At start of grade 1 (children non-readers), good PA predicted good reading 7 mo later, but many with poor PA also did well. Children differ in the ease with which they pick up PA when introduced to literacy. • Positive correlation between preschool phonology and later reading could be consequence of some preschoolers reading (see also Castles and Coltheart, 2004)

20. Bishop et al (in press) comparison of pure LI and LI + reading disability (RD) • Retrospective analysis of measures taken at 4 years. Did not differ on: • Nonverbal ability • Vocabulary • Oral comprehension • Sentence memory • Phonological awareness • Nonword repetition NB significantly impaired at 4 yr on all these when compared to control group

21. time 1 = 4 yr time 2 = 6 yr LI do not differ from LI+RD at any time

22. 4 yr: CNRep 20 items 6 yr: CNRep 40 items 9 yr: NEPSY time 1 = 4 yr time 2 = 6 yr time 3 = 9 yr Significant interaction: time x group LI do not differ from LI+RD at time 1, but do differ at times 2 and 3

23. 4 yr: Goldman Fristoe articulation 9 yr: NEPSY oromotor time 1 = 4 yr time 3 = 9 yr LI worse than LI+RD at time 1, but do worse still at time 3

24. Differences in phonological processing emerge over time • Nonword repetition and oromotor (articulation): groups diverge with age

25. 4. Children with sensory or motor problems affecting phonology

26. Children with impaired speech production In general, these do not seem to impair decoding unless accompanied by broader language difficulties: • Structural problems – e.g., cleft palate (Stackhouse, 1982) • Neurological problems, e.g. cerebral palsy (Bishop & Robson, 1989) • Problems of unknown (?genetic) origin, - speech sound disorder (see review by Pennington & Bishop, in press)

27. Children with impaired phoneme discrimination • Study comparing children with mild-moderate hearing loss and those with SLI Briscoe et al, 2001 • Hearing impaired had sensorineural hearing loss from 25 to 65 dB across speech frequencies

28. Phonological discrimination • Bridgeman & Snowling test • Same/Different judgements re real and nonwords with final s, t, st, or ts • ‘Different’ differ either in single segment (e.g. ‘tot’ vs. ‘toss’) or in sequence (e.g. ‘gets’ vs. ‘guest’)

29. Phonological discrimination * * * significant difference from group CA

30. Phonological awareness task (Introducing monster): This is ‘Wug’. He likes things that sound like his name. Which do you think he will choose? The cake, the jug, the leaf or the boat?

31. Phonological awareness * * * significant difference from group CA

32. WORD single word reading

33. Nonword reading

34. Conclusion re hearing loss • Mild-moderate hearing loss affects phonological discrimination and awareness, and nonword repetition (Briscoe et al) • Yet children with mild-moderate hearing loss do much better than those with SLI on literacy see also Halliday & Bishop, 2005 Wake et al., 2006

35. Questions for discussion • Is phonological deficit a causal deficit in SLI or dyslexia? • Is profile of phonological deficits in SLI/dyslexia the same as that in illiterates? • What are implications for intervention? • Do we really understand how a phonological deficit could cause literacy problems? • How important is nonsegmental level for understanding SLI? • Why so little funding for research on these disorders compared with autism?