Literacy difficulties exist along a spectrum, which can make them difficult to pin down. Precise definitions of dyslexia are changing all the time, but a number of common characteristics have been agreed. Those with dyslexia struggle to break down words into their smallest constituent parts, making language learning an often difficult process. Dyslexia runs in families and frequently co-occurs with difficulties in other skills, including organisation, calculation and concentration.
The Rose definition
In 2008, the Labour government tasked Sir Jim Rose with investigating how to improve provision for dyslexic children. The Rose Report that followed provides a widely-accepted definition:
Dyslexia is a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling. Characteristic features of dyslexia are difficulties in phonological awareness, verbal memory and verbal processing speed. Dyslexia occurs across the range of intellectual abilities. It is best thought of as a continuum, not a distinct category, and there are no clear cut-off points. Co-occurring difficulties may be seen in aspects of language, motor co-ordination, mental calculation, concentration and personal organisation, but these are not, by themselves, markers of dyslexia.