Dyslexia is primarily associated with difficulties in:

Concept: A specific learning disorder is diagnosed when a learner's attainment in a particular academic skill stays markedly below age expectation despite adequate instruction, intact vision and hearing, and no general intellectual deficit. The diagnosis is recorded with a specifier naming the skill area affected — reading, written expression or mathematics — and more than one area can be affected in the same learner. An everyday label attached to such a disorder therefore identifies the skill area it refers to; it does not describe a broad or global impairment.

Application: Dyslexia is the term used for a specific learning disorder with impairment in reading. Its core deficit is phonological processing — hearing, holding and manipulating the sound units of speech — which makes the mapping of letters onto speech sounds unreliable. Decoding therefore becomes inaccurate and effortful, effortful decoding is slow, and slow decoding consumes the working-memory capacity that understanding a passage requires. Accuracy, fluency and comprehension are consequently affected together as one chain, which is why the reading specifier lists all three.

Cross-check: Each of the other domains offered is the province of a differently named condition, so none of them is the skill area the term dyslexia refers to:

• Motor coordination and balance control — developmental coordination disorder (dyspraxia), a motor-planning condition rather than an academic-skill disorder.

• Social interaction and communication skills — autism spectrum disorder, a neurodevelopmental condition of social communication.

• Mathematical reasoning and problem solving — dyscalculia, the term used when the mathematics specifier applies.

Result: Dyslexia is primarily associated with difficulties in reading accuracy, fluency, and comprehension.