Summary of the key findings from the project
The Wellcome Reading and Language Project produced a number of important findings.
- Many children with pre-school SLI resolved their language difficulties by school age. Among children whose language difficulty persisted, 53% were identified as dyslexic.
- In the pre-school phase, phonological deficits (primarily problems with memory processes) were observed in children at family-risk of dyslexia and children with SLI. These are major risk factors for dyslexia. In addition, children with SLI scored poorly across multiple domains of language and on tests assessing executive attention and motor skills; such co-occurring impairments were much less common in the family-risk group. Co-morbidities in executive attention and motor skills can be expected to affect school readiness and learning across the curriculum. Consistent with this, executive attention at 4.5 years old and motor skills at 6 years old are significant predictors of individual risk of dyslexia. Measures of language and executive attention also predicted arithmetic development.
- Socioeconomic status, home literacy environment and early child health independently predicted school readiness. It was notable that the effects of socioeconomic status on early literacy were mediated by two parenting practices: storybook reading and direct print instruction. Both were more important for the development of phonological awareness in family-risk children than for controls.
- We have shown that a nine-week intervention can support the development of basic reading skills, phonological awareness and vocabulary development in children at risk of dyslexia at 6 years old. However the effects were small and gains in decoding skills were not significantly different in the control group who received phonics instruction in the classroom. Response to intervention was predicted by initial level of reading and phonological skills.
- Approximately one third of children at family risk of dyslexia have a pre-school language impairment. (See Nash et al., 2013.)
- Children at family risk of dyslexia have problems in tasks requiring them to process sounds (e.g., to repeat non-words and to manipulate the sounds in spoken words).
- These children also find it difficult to learn letter sounds.
- Children with pre-school language difficulties have weaknesses in fine motor skills and attention. This suggests that they may be at increased risk for co-morbid difficulties such as attention deficit hyperactivity disorder (ADHD) or dyspraxia. (See Gooch et al., 2013.)
In summary, our findings regarding the pre-school profile of children at risk of dyslexia suggest that there may be several factors which affect learning. These are:
- oral language difficulties;
- difficulties hearing and manipulating the sounds in spoken words;
- difficulties translating visual into verbal information (seen in rapid naming tasks and in learning letter–sound relationships);
- co-occurring motor and attention difficulties which can be expected to affect school readiness.
It should though be noted that many children with pre-school language impairment resolve their language difficulties by school age. Importantly, there are also children who develop dyslexia who do not have problems in the pre-school years with spoken language skills.
Professor Maggie Snowling explains the causes of reading difficulties in SLI and how they link to dyslexia and spoken language problems here.
Although ‘early identification’ has always been the hope of dyslexia researchers and educators, together these findings mean that the detection of dyslexia in preschool is difficult – though being at family-risk gives us the best clue (see Thompson et al., 2015).
The project also focused on the children’s environment. Socioeconomic status (SES), home literacy environment (HLE) and early child health independently predicted school readiness and home literacy environment acted as a mediator of outcomes.
More specifically, the effects of SES on early literacy were mediated by two parenting practices: storybook reading and direct print instruction.
In 2011, 60 children from high-risk groups already showing reading delay one year after starting school were selected to receive a specially designed intervention to promote language and literacy skills – RALI (Reading and Language Intervention). The children started the intervention once they had completed the Phase 4 assessment; the first 30 children took part from April–December 2011 and the second 30 children took part from September–March 2012. In each of these groups, children were allocated either to receive intervention for 18 weeks or to a control group who waited for nine weeks before receiving the intervention (nine-week intervention).
The children were based in 46 different schools and in each school the target child received the intervention together with two peers from the same class. We trained a teaching assistant from each school to deliver the intervention and she received support from the research team.
We showed that intervention can support the development of basic reading skills, phonological awareness and vocabulary development in children at risk of dyslexia. The effects, however, were small and gains in decoding skills were not significantly different from the control group who received phonics instruction in the classroom.
We also considered the extent to which we could predict how well a child responds to intervention. Response to intervention depended upon initial levels of reading and phonological skills – children with more severe problems were harder to teach.
Outcomes at age 8–9 years
Our final assessment of the children confirmed the importance of language for success in reading:
- 26% of children at family-risk of dyslexia, 26% of the LI group and 40% of the FR+LI group had reading problems. Among children with persistent SLI, 53% were identified as dyslexic.
Oral language skills at 3.5 years predicted children’s reading comprehension at 8 years old. Some of this effect was because language skills underlie the development of phoneme awareness and this in turn leads to better word reading (decoding of print). There is also, however, a direct influence of language skills on reading for meaning.
implications and gaps in the evidence
The Wellcome project has highlighted some areas for further research.
- The risk of poor reading and arithmetic is elevated in children at family-risk of dyslexia and there is around a fivefold increase in reading problems among children with language impairments. We need to understand better the role of difficulties in executive attention, an additional risk factor for children with language impairment.
- About 40% of children with pre-school SLI resolve their language difficulties by age 5, as do most children with speech difficulties. Those whose speech/language problems persist, however, experience literacy problems. Although the accurate prediction of individual risk from pre-school remains difficult, early intervention for language difficulties should be a priority to ensure school readiness.
- The impact of socioeconomic status on outcomes is partly mediated by the home literacy environment; in turn, this is an important factor in predicting early steps in reading. Support for parents in preparing their children for school is essential, particularly for parents who are not aware of dyslexia (or indeed that they may themselves be affected).
Together the findings underline the importance of the early years for fostering oral language and pre-reading skills for children at family-risk of dyslexia and also more generally children who are socially disadvantaged.