Learning to read is not easy, and a substantial number of children struggle to do it. Children who read substantially less well than most children of their age may be referred to as exhibiting ‘specific learning difficulties’ or ‘specific reading impairment’ or ‘developmental dyslexia’ (‘dyslexia’ for short). These different terms are typically used interchangeably. Learning to write and spell is not easy, either, and some children lag behind their peers here, too. The distinction between difficulty in learning to read and difficulty in learning to write and spell is worth making because there are children who are normal readers for their age but poor spellers: these children are dysgraphic (poor at writing and spelling) while not being dyslexic (poor at reading). Children who have had difficulty in learning to read but have managed to catch up with their peers as far as reading is concerned often still exhibit poor writing and spelling.

It is natural to ask: what is the incidence of difficulties in learning to read amongst Australian children? This question has no answer. How far a child is lagging behind in reading compared to other children of the same age is a matter of degree. There is no way of making any qualitative distinction between ‘children with dyslexia’ and ‘children without dyslexia’; the distinction is purely quantitative (ie, depends on how far behind in reading a child is required to be before he warrants the label dyslexia) and therefore arbitrary. This is because reading is a skill that is distributed continuously rather than dichotomously across any group of children.

Or, to be more exact, reading is a set of skills, each distributed continuously rather than dichotomously across any group of children. If that is so, it follows that if we want to understand how children learn to read (and why some find this so difficult), we first need to identify the set of reading skills that children will need to acquire. That in turn means that we first need to understand skilled reading – we need to know exactly what are the cognitive skills that skilled readers possess which enable them to achieve the act of reading so quickly and so effortlessly.