Literacy, language and speech processing: What are the links?

1. Literacy, language and speech processing: What are the links? Julia M Carroll Joanne M Myers University of Warwick, UK

2. Previous Research Some, but not all, children with early speech difficulties go on to have literacy difficulties • WHY? • The delay versus disorder hypothesis (Dodd) • Children with unusual speech errors are likely to show reading difficulties • The language hypothesis (Nathan, Catts) • Only children with speech and language problems have reading difficulties. Children with pure speech problems do not go on to have difficulties • The phonological representations hypothesis • Only children with difficulties in representing phonology will have difficulties in reading Much previous research based on group differences – ignores severity and interacting variables

3. The Rationale • Previous research has looked at reading outcomes in highly selected groups. • In contrast, we start with a high risk, but unselected group, and use a multivariate approach: • 4-6 year old children in Reception, Year 1 and early Year 2 • 46 children with a family history of dyslexia • 36 children who have had speech and language therapy • 28 children with low nonword repetition, but no other risk factors • 88 typically developing children with at least average nonword repetition • 114 children have been retested after six months to assess progress in literacy

4. Tasks used • Literacy skills • Word reading, spelling (phonetic and conventional) and letter sound knowledge • Speech skills • Diagnostic Evaluation of Articulation and Phonology • Percentage phonemes correct and types of speech error • Language skills • CELF pre-school • Expressive and receptive word level and sentence level tasks • Phonological tasks • Phonological Awareness (Initial sound matching) • Nonword Repetition • Mispronunciation detection • Priming – accuracy of word production • Word Learning – number of confusions when learning nonword names

5. Analyses • Group comparisons • Do we replicate previous results? • Predicting reading and spelling development • Do language, speech and phonological processing predict literacy progress in this high risk sample? • Predicting phonological awareness • Phonological awareness is a major predictor of literacy progress • What are the predictors of progress in phonological awareness? • Factor analysis • Can speech and language skills usefully be separated?

6. Group Comparisons – Delay versus Disorder • Are children with unusual speech errors more likely to have literacy difficulties? * *

7. Group Comparisons – Language hypothesis • Are children with low language more likely to have literacy difficulties?

8. Group Comparisons • Are children with unusual speech skills more likely to have language difficulties? *

9. Group Comparisons • Do children with unusual speech patterns have poorer literacy? • In spelling and phonological awareness, yes: Children with unusual errors do less well than those with no errors, while children with speech delay do not. • No group differences in reading • Do children with language difficulties have poorer literacy? • Clear group differences in each variable • Do those children with unusual speech errors also have low language skills? • To a certain extent Partial replication of previous group difference results

10. Multiple Regression Analyses • Can we predict growth in reading, spelling and phonological awareness? • Controlling for age and the auto-regressor • Separate regression analyses (not pitting variables against one another)

11. Predicting Reading

12. Predicting Spelling

13. Predicting phonological awareness Phonological processing predicts growth in phonological awareness

14. Predicting Progress • Language does not predict progress once initial levels are controlled • Nonword repetition is a predictor of all three measures Phonological processing is a better predictor of growth in literacy than language • Reading progress is predicted by letter knowledge and phonological awareness • Spelling progress is predicted by letter knowledge and nonword repetition • Phonological awareness progress is predicted by speech and phonological processing measures

15. Factor Analysis

16. Factor Analysis • The variables did not divide according to ‘speech’, ‘language’, ‘phonological processing’ • Instead there was a factor concerned with phonological and output processes, and one concerned with lexical/syntactic processes • The predictive power of ‘language’ depends on what skills are included in the term

17. Phonological processing A possible model Lexical / syntactic processes Text Reading Phonological awareness Word level Literacy Letter knowledge Language difficulties are an important signal for potential difficulties in word level literacy. But there is not a direct causal relation. The link is explained by a third variable, phonological processing