1. What Is Dyslexia?

Purpose: To give readers a clear and accurate understanding of dyslexia.

1.1) Is dyslexia simply a reading problem?

Dyslexia is a reading problem, but it can be a severe and complex one. It affects the ability to read words accurately, fluently and automatically. In severe cases, a child may be unable to read even simple words despite years of schooling and intervention.

Reading depends on many processes working together. Two important but distinct abilities are recognising, interpreting and manipulating sounds, and recognising written words instantly, much as one recognises a familiar face. When one or both of these abilities do not develop sufficiently, learning to read can become extraordinarily difficult.

The effects may also extend beyond reading. In school, dyslexia can affect spelling, writing, studying and access to information across the curriculum, including mathematics. In adulthood, it may also affect daily life, making it difficult to read a menu, follow written directions, complete a form, interpret medicine labels or understand important written messages.

Dyslexia is therefore fundamentally a reading problem, but it is certainly not a simple one.

1.2) What exactly is dyslexia?

Dyslexia is not a sign of low intelligence. In fact, many people with dyslexia are highly intelligent. It is not caused by poor eyesight, laziness or a lack of effort. Although not all teaching is equally effective, dyslexia is also not the result of poor teaching methods.

Dyslexia is a learning difficulty that primarily affects a person’s ability to read and spell accurately and fluently. A child with dyslexia may read slowly, confuse or omit words, have difficulty sounding out unfamiliar words, and continue making spelling errors despite receiving adequate instruction. Its effects may extend across the curriculum, including mathematics.

Dyslexia exists on a continuum and can be mild, moderate or severe. It does not present in exactly the same way in every person. Each individual has a particular combination of strengths and weaknesses, which influences the nature and severity of the reading difficulty.

Most importantly, although dyslexia can present significant difficulties, meaningful improvement is possible with the right intervention and sufficient practice.

1.3) Different types and profiles of dyslexia

Researchers describe several types or profiles, depending on when the reading difficulty developed and which aspects of reading are most affected.

Developmental dyslexia originates during childhood as the abilities required for reading are developing. The difficulty becomes apparent when the child begins learning to read and may continue into adulthood. Acquired dyslexia develops when a person who could previously read loses some or all of that ability because of a stroke, brain injury or other neurological event.

Researchers also distinguish between phonological and surface dyslexia.

Phonological dyslexia primarily affects the ability to process sounds and connect them with written letters. A child may recognise some familiar words from memory but be unable to blend the sounds in a simple unfamiliar word. Because the child has difficulty matching letters and sounds, spelling may be particularly poor. Surface dyslexia primarily affects the ability to recognise written words instantly. A person may rely heavily on sounding out every word and have particular difficulty with irregular words such as would and does, which cannot be read correctly by applying the most common sound–letter rules. Spelling will typically be phonetic—for example, laf instead of laugh.

A person may have a mixed profile in which both sound processing and instant word recognition are affected. This generally results in more severe reading difficulties.

1.4) Dyslexia and intelligence

For many years, dyslexia was associated with brightness. A child was considered dyslexic when they had average or above-average intelligence but performed poorly in reading. There had to be a so-called discrepancy between potential and achievement. Children with both lower IQ scores and poor reading ability were described as “garden-variety poor readers”.

This distinction was challenged by a 2011 brain-imaging study conducted by Hiroko Tanaka, Professor John Gabrieli and their colleagues. The study involved 131 children from two independent samples. The children were classified as typical readers, poor readers with typical IQ scores, or poor readers with lower IQ scores.

Using functional magnetic resonance imaging, or fMRI, the researchers examined activity in six brain regions involved in connecting print and sound. The two groups of poor readers showed similar patterns of reduced activity, regardless of their IQ scores. Their brains did not distinguish between the so-called “bright dyslexic” and the poor reader with a lower IQ.

The findings were later supported by research conducted by Simos and colleagues using magnetoencephalography. Their results also indicated that the reading-related brain differences found in poor readers were not determined by IQ.

These findings support the conclusion that reading disability is independent of IQ. A child does not have to be highly intelligent to be dyslexic, and a lower IQ score does not make a serious reading difficulty any less real. Dyslexia can thus occur across the full range of intellectual ability. It should therefore be identified by the reading difficulty itself, not by the size of the gap between a person’s reading ability and IQ.

1.5) How common is dyslexia?

Dyslexia is very common. Most estimates suggest that it affects approximately 5% to 10% of the population—so potentially one person in every ten. Some estimates are considerably higher, at 15% or even 20%.

The difference depends largely on how dyslexia is defined. Stricter diagnostic criteria identify a smaller group, while broader criteria include people who display some characteristics of dyslexia or have less severe reading difficulties.

Dyslexia occurs across countries, cultures and languages. However, the structure and spelling system of a language influence both how dyslexia presents and how many people meet the diagnostic criteria. In a transparent language, where letters and sounds correspond consistently, reading places fewer demands on the learner. Reading difficulties may therefore be less severe, and fewer people may fall below the threshold for a dyslexia diagnosis.

An Italian research group studied nearly 10 000 learners and found a dyslexia prevalence of only 3,5%. Italian has a highly transparent spelling system, which makes accurate decoding easier than it is in an opaque and irregular language such as English.

Whatever figure we use, dyslexia is not rare. In an ordinary classroom, there will very likely be one or more children with dyslexia—and some of them may not yet have been identified.

1.6) Undiagnosed dyslexia in adults

Many adults have dyslexia without ever having been formally identified. This is particularly common among people who attended school at a time when dyslexia was poorly understood. They may have been described as lazy, careless or unwilling to work hard. Some left school believing that they lacked intelligence when the real problem was an unidentified reading disability.

People with milder dyslexia may develop ways to compensate for their reading difficulties. They may rely heavily on context, memorise words, avoid reading aloud or select work that does not require extensive reading and writing. These coping strategies can allow the underlying difficulty to remain hidden.

Nevertheless, signs of dyslexia often persist into adulthood. An adult may read slowly, need to reread information several times, avoid unfamiliar words, make persistent spelling errors or require considerably more time to complete written tasks. Increased reading and writing demands at university or in the workplace may eventually reveal a difficulty that was previously manageable.

For many adults, discovering that they have dyslexia brings relief. A diagnosis or identification provides an explanation for difficulties experienced throughout their lives and helps them understand that the problem was never a lack of intelligence or effort.

2. Dyslexia Symptoms and Signs

Purpose: To help readers identify warning signs at different ages.

2.1) Early warning signs of dyslexia

The earliest warning signs of dyslexia may appear before a child begins formal reading instruction. However, dyslexia cannot be identified from one sign alone.

One of the strongest warning signs is a family history of persistent reading and spelling difficulties. A young child may also have delayed speech development, difficulty pronouncing longer words, or trouble learning and remembering new words.

Other possible signs include difficulty recognising rhyming words, breaking words into syllables, identifying the first sound in a word, and learning letter names and sounds. The child may also have trouble remembering sequences, such as the days of the week, or rapidly naming familiar colours and objects.

Young children develop at different rates, and factors such as hearing and language exposure must also be considered. However, when several warning signs persist—particularly when dyslexia runs in the family—they should be taken seriously.

Parents should not wait for a child to fail before providing support. The underlying skills needed for reading can be developed before the reading gap appears.

2.2) Signs that appear when a child begins reading

The signs of dyslexia usually become more noticeable once formal reading instruction begins. A child may have difficulty learning letter sounds or combining sounds to form words. Reading may be extremely slow and effortful, with the child repeatedly sounding out the same word without recognising it when it appears again.

The child may guess words from the first letter or accompanying pictures, substitute one word for another, add or omit words, or lose their place while reading. Even frequently occurring function words such as the, of, was and from may be misread.

Letter, word and number reversals may also occur. A child may confuse letters such as b and d, write letters or numbers backwards, or read was as saw. Reversals alone do not prove that a child has dyslexia. They become more significant when they persist beyond the early stages of literacy and occur alongside other reading and spelling difficulties.

Another important sign is a difference between oral and written performance. A child may understand a story when someone else reads it aloud but comprehend very little when reading it independently. The effort required to identify the words leaves fewer mental resources available for understanding the text.

Occasional errors are normal while children are learning to read. Concern is warranted when several difficulties persist, progress remains unusually slow and the child requires considerably more repetition than expected.

2.3) Accurate reading does not rule out dyslexia

A child may appear to read accurately while their reading difficulty remains hidden. This is particularly common in Grades 1 and 2, when readers are short and repetitive and the same text is often practised several times. Some children memorise the lesson and recite it while appearing to read. Others use pictures, context or the first letter of a word to predict what it says. Parents and teachers may therefore not realise that the child is not actually reading every word.

The difficulty usually becomes more apparent when the child encounters unfamiliar or longer text, or text without pictures. Even then, some children can pronounce every word correctly but read so slowly and effortfully that reading remains a serious difficulty. They may apply letter–sound rules carefully but have to sound out the same words repeatedly instead of recognising them quickly and automatically.

When most of a child’s concentration is devoted to deciphering the words, too little remains for understanding the message. Concentration can be compared to butter spread over a slice of bread: it can be spread only so far. If most of it is used for word recognition, there may not be enough left for comprehension.

The child may therefore reach the end of a sentence or paragraph without understanding or remembering what was read. This explains why some children understand a story when someone else reads it aloud but have difficulty understanding the same story when reading it independently.

Reading ability cannot be judged by accuracy alone. Fluency, automaticity, comprehension and the amount of effort required must also be considered. A child may read the words correctly—or appear to do so—and still have dyslexia.

2.4) Effects on spelling, writing and mathematics

Dyslexia commonly affects spelling because reading and spelling depend on many of the same underlying abilities. Reading requires written symbols to be connected with sounds, while spelling requires the reverse process: connecting sounds with the correct letters and letter patterns.

A child with dyslexia may omit, add or reverse letters, confuse letters with similar sounds, or place letters in the wrong order. The child may spell the same word differently on the same page, while even common words may remain difficult despite repeated teaching and practice.

Writing may also be affected. Because the child must devote considerable attention to spelling, they may use short sentences and simple words that are easier to spell. A child may express excellent ideas verbally but produce very little on paper. Grammar, punctuation and organisation may also be affected when so much mental effort is devoted to forming and spelling individual words.

Dyslexia can also affect mathematics. A child may misread a word problem or written instruction, confuse mathematical symbols, reverse digits, or place numbers in the wrong order.

Mathematical difficulties associated with dyslexia must be distinguished from dyscalculia, which is a specific difficulty with learning mathematics. Dyslexia and dyscalculia can occur together, but they are not the same condition.

2.5) The emotional impact of dyslexia

The emotional impact of dyslexia can be profound, both before and after it is identified.

Repeated reading failure may cause a child to believe that they are unintelligent or incapable. Receiving a diagnosis is not always a relief. Some children experience the label as confirmation that something is seriously wrong with them or that they will never learn to read successfully. This can lead to intense fear, shame and hopelessness.

Over time, dyslexia may affect confidence and self-esteem. A child may become anxious when asked to read aloud or complete written work. They may avoid reading, complain about school, or develop headaches and stomach aches before a test or reading lesson.

A diagnosis must therefore be explained with great care. The child needs to understand that dyslexia describes a difficulty they are experiencing; it does not define their intelligence, potential or future. They also need to know that meaningful improvement is possible.

Children do not all respond to reading difficulty in the same way. One may become angry, another may joke or distract the class, another may withdraw, and another may become anxious or perfectionistic. Temperament can strongly influence how a child expresses and manages the emotional effects of dyslexia. These responses should not automatically be interpreted as laziness, poor motivation or bad behaviour.

3. Causes of Dyslexia

Purpose: To explain that dyslexia does not have one simple cause. It may involve hereditary factors, differences in the brain and weaknesses in the cognitive skills required for reading—while emphasising that none of these makes a child’s reading future unchangeable.

3.1) What causes dyslexia?

There is no single cause of dyslexia. Research points to several possible contributing factors, including heredity, differences in the brain and weaknesses in the cognitive skills required for reading.

Dyslexia often runs in families, suggesting that genes can increase a person’s risk of developing reading difficulties. However, inheriting a genetic risk does not mean that a child’s future is predetermined.

Researchers have also identified differences between the brains of people with dyslexia and those of skilled readers. These findings must be interpreted carefully. Some differences may contribute to dyslexia, while others may develop because a person reads less and has had fewer successful reading experiences.

The most immediate difficulties are often found in weaknesses in the underlying skills required for reading. These include phonological and phonemic awareness, visual processing, sequencing, several types of memory and reasoning.

Different combinations of weaknesses may therefore lead to different forms and degrees of dyslexia. This helps explain why dyslexia does not look the same in every person and why no single theory explains every case.

3.2) The role of heredity in dyslexia

When dyslexia runs in a family, a child may be at greater risk of developing reading difficulties. Parents and teachers should therefore monitor the child’s development carefully and provide support as early as possible.

A genetic predisposition does not determine the eventual outcome. Heart problems, for example, may run in a family. Although inherited risk cannot be changed, a person can pay closer attention to exercise, nutrition and other protective factors.

The same principle applies to dyslexia. The genes a child inherits cannot be changed, but the cognitive and language skills required for reading can be developed. Explicit, systematic reading instruction and intensive practice can also help the child develop accuracy, fluency and automaticity.

Heredity may help explain why a reading difficulty developed, but it does not determine how much progress a child can make. Awareness of a family history allows parents to recognise the risk, watch for early warning signs and act before the reading gap becomes severe.

3.3) Brain differences and dyslexia

Brain-imaging studies have identified differences between people with dyslexia and typical readers. Two areas frequently discussed are regions in the parietal lobe and the visual word form area.

Regions in the left temporoparietal reading network are involved in linking letters and sounds and in decoding unfamiliar words, while the visual word form area enables skilled readers to recognise familiar written words quickly and automatically. In people with dyslexia, these areas are often less active during reading. Other areas of the brain may work harder to compensate, helping the person read more accurately, but not necessarily quickly or automatically.

A brain difference is not automatically a brain defect, nor does it necessarily reveal what caused the reading difficulty. Some brain differences may contribute to dyslexia, while others may be consequences of reading less.

Krafnick and colleagues explored this possibility in a 2014 study published in the Journal of Neuroscience. They compared children with dyslexia with typical readers of the same age and younger children reading at the same level as the dyslexic group. The children with dyslexia had less grey matter than typical readers of the same age, but their grey matter volumes were similar to those of the younger children who read at the same level. This suggests that some anatomical differences associated with dyslexia may reflect differences in reading experience rather than an underlying brain defect.

This finding can be understood in terms of neuroplasticity—the brain’s ability to change through learning, experience and repeated practice. Learning to read changes the brain, and effective intervention can produce measurable changes in both reading performance and brain activity.

Brain function is not fixed: learning and intervention can change the way the reading network operates. The brain reflects what a person has learned and repeatedly practised, as well as the abilities that have not yet been developed.

3.4) The cognitive foundations of reading

Learning is a stratified process: certain foundational skills must be developed before more advanced skills can be learned. This principle is evident in sport. A person cannot play soccer without first learning to dribble, pass and shoot the ball. Similarly, an ice hockey player must learn to skate before learning to control, pass and shoot the puck.

Reading also depends on foundational skills. These must be developed before a person can learn to read effectively—and eventually to spell and write.

At the bottom of the reading ladder is language. A person can only understand written material if they know the language in which it is written. Someone may learn the sounds of an unfamiliar language and pronounce its words correctly, but this does not mean that they understand what they are reading. Reading requires an adequate vocabulary and a sound understanding of the language’s structure.

The next level consists of cognitive skills, which can be divided into four main building blocks: attention or concentration, perception or processing, memory and logical thinking.

Attention and concentration

Attention includes focused, sustained and divided attention. Focused attention allows a person to concentrate on the information relevant to a particular task. Sustained attention makes it possible to maintain that concentration over time. Divided attention allows a person to attend to more than one aspect of a task simultaneously.

Reading requires the reader to focus on written information, maintain attention across sentences and paragraphs, and coordinate several processes at the same time.

Perception and processing

Perception, or processing, essentially means interpretation. Human beings are born with their senses and can see and hear, but the ability to interpret visual and auditory information develops through experience and learning.

Two forms of processing are particularly important for reading. Visual processing enables a person to interpret what they see, while phonological processing relates to spoken language and enables learners to recognise, interpret and manipulate speech sounds.

These perceptual skills must become automatic. Learning to drive provides a useful comparison. A new driver consciously thinks about every action, but many of these actions eventually occur without conscious effort. In the same way, perceptual skills must become so well established that a child can use them automatically while reading.

Memory

Several types of memory contribute to successful reading, and strength in one type does not necessarily imply strength in another.

Visual memory enables a person to remember what they see. A child with poor visual memory may find it difficult to remember the shapes of letters and words or retain written information. Auditory memory enables a person to remember what they hear. Poor auditory memory may make it difficult to learn and remember phonics.

Sequential memory is the ability to remember information in the correct order, such as the days of the week, the months of the year or the letters of the alphabet. Nearly every word consists of a unique sequence of letters, making sequential memory important for both reading and spelling.

Short-term memory retains information briefly, while long-term memory stores it for extended periods. Working memory enables a person to hold information in mind while using or manipulating it. It is closely associated with academic performance and is often described as the engine of learning.

Logical thinking

Logical thinking is the ability to think and reason. It supports reading comprehension by enabling readers to connect ideas, draw conclusions and make inferences. This relationship is reflected in the statement that “reading is reasoning”.

The good news is that all these cognitive skills—attention, processing, memory and logical thinking—can be developed and improved.

4. A Dyslexia Solution

Purpose: To offer practical guidance and genuine hope to parents with dyslexic children.

4.1) Can dyslexia be improved?

Yes, dyslexia can be improved. A child’s present reading level should never be regarded as a fixed limit.

The brain can change through learning and repeated practice. The cognitive skills required for reading—including attention, processing, memory and logical thinking—can also be developed.

Cognitive training on its own, however, is not enough. Nor is simply giving a child more reading practice sufficient. Effective intervention must address both sides of the reading difficulty: it must develop the underlying cognitive skills that make reading possible while also teaching reading itself.

These two components must work together if reading is to become accurate, fluent and automatic.

4.2) Teaching reading to children with dyslexia

An effective reading intervention programme should be explicit, systematic and cumulative.

Explicit instruction means teaching the child directly instead of expecting them to discover the rules of reading independently. Children learn many things incidentally through exposure and experience. Incidental learning, however, cannot be relied upon when teaching a child with dyslexia to read. The written code must be taught intentionally and practised until it becomes automatic.

Systematic instruction follows a planned sequence, beginning with simpler skills and gradually progressing to more difficult ones. For example, words such as kit, hop and cub are taught before kite, hope and cube, because the silent e introduces a more advanced spelling pattern. Similarly, music would be taught before antique. Both words end with the /k/ sound, but music represents it with c, while antique uses the more advanced que spelling.

Cumulative instruction ensures that each new skill builds on previously taught material while earlier skills are continually reviewed and practised. A lesson should therefore include both the new spelling pattern and patterns the child has learned previously. This strengthens retention and helps the child distinguish between different patterns.

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Authored by Sue du Plessis (B.A. Hons Psychology; B.D.), an educational specialist with 30+ years’ experience in the field of learning disabilities. Medically reviewed by Dr. Zelda Strydom (MBChB).

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References:

• “Dyslexia Symptoms and Signs,” Edubloxtutor.com
• Elliott, J & Grigorenko, E., The Dyslexia Debate (New York: Cambridge University Press, 2014).
• Fleming, N., “Dyslexia ‘worse for drivers than drink’,” The Telegraph, 3 February 2005, https://bit.ly/348wk9m
• Gabrieli, J. D. E., et al., “The brain basis of the phonological deficit in dyslexia is independent of IQ,” Psychological Science, November 2011, vol. 22 (11), 1442-1451.
• Hornsby, B., Overcoming Dyslexia (Johannesburg: Juta and Company Ltd., 1984).
• Howie, S., et al., Progress in International Reading Literacy Study (University of Pretoria: Centre for Evaluation and Assessment, 2011), https://bit.ly/2NqygDk
• Krafnick, A., et al., “An investigation into the origin of anatomical differences in dyslexia,” The Jounal of Neuroscience, 15 January 2014, vol. 34(3), 901-908.
• Lerner, J., Learning Disabilities: Theories, Diagnosis, and Teaching Strategies (4th ed.), (Boston: Houghton Mifflin Company, 1988).
• Shaywitz, S., Overcoming Dyslexia (New York: Vintage Books, 2003).
• Smith, C. R., Learning Disabilities. The Interaction of Learner, Task, and Setting (Boston: Allyn and Bacon, 1991).

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