Let’s consider the issue of letter reversals – a common challenge for many children, and frequently a concerning one for parents.
Letter reversals are not a “normal part of development”. That is to say, not all children experience reversals on their path to literacy. That being said, the majority of children will demonstrate reversals at some point in their literacy development. Typically, reversals are “suppressed” or resolved near the end of Kindergarten/beginning of Grade 1.

 
There are 2 parts of letter reversals to explore:
There is a visual processing piece to reversals

 
There is a large chunk of neurons in the visual system that is dedicated to recognizing the faces of other human beings. This “original facial recognition software” that we have built into our brains has a unique feature. The brain uses a “mirroring system” that allows for continuity in recognizing someone when viewing them straight on, from the left side profile, and/or from the right-side profile instead of thinking this is a “new” or unfamiliar person.

 
This facial recognition system is innate or “built-in” – we are born with it.
As children are exposed to letters, there comes a need to recognize them and operate with them. In order to do this, the brain needs dedicated cells or neurons for letter recognition. These cells are NOT innate – they do not exist in the brain. As such, the brain undergoes a process known as “neuronal recycling” and the facial recognition system moves to new that are located more to the left side of the brain. This “frees up” those neurons that were previously used for facial recognition for a new task – letter recognition.

 
As these “recycled” neurons re-specialize around letter recognition, the brain must suppress the mirroring function. Initially, “b” and “d” and “p” and “q” are interpreted or associated as identical letters. With exposure and experience, an intact system will relatively quickly begin to identify these letters accurately as separate.
There is a language root to reversals
When this mirroring process is NOT suppressed, and reversals persist DESPITE letter exposure and instruction, it is an indication that the key information that would differentiate letters is being missed. The information that differentiates “b” from “d” would be “points to the LEFT/RIGHT” (left and right are language concepts); makes the sound /b/ vs. /d/ (sound processing concepts); has the label “b” vs. the sound “d” (sound processing and language meaning/letter concepts).
In other words, the way to tell “b” and “d” apart is by the verbal and auditory information they contain. And when the brain “misses” this information, it tells about the development and efficiency of the underlying sound-language system. That is why letter reversals that persist past mid-Gr 1 are a red flag for a deeper, more significant language-based literacy disorder.
Expanding on the language-based nature of reversals
When difficulties with reversals are present, children may “miscall” a letter, such as labelling “b” as “dee”; or they may represent letters incorrectly in spelling by writing the letter “b” as “d”.

 
Many people mistakenly believe that reversals reflect a problem in visual processing; such people may also believe that dyslexia has some sort of “visual processing component” and things are not “seen or processed correctly” (you may have even heard of recommendations for “vision therapy” or tinted lenses to help with this). Make no mistake: These are misconceptions.
Research shows us that challenges with letter and number reversals reflect a language deficit. Reading is a language task. It is the act of word recognition and activation of meaning. Words – and meaning – are in the domain of language.
Reading, writing, and spelling are language tasks that have been complicated by the addition of an artificial man-made symbol system that we call the alphabet. The alphabet is a “code” of shapes to visually represent our spoken sounds and words.
The vast majority of the time, children do not have any difficulty processing the visual representations of letters (e.g., if they can copy a letter while looking at it, the visual systemin the occipital lobe is working correctly!). Rather, where we see difficulty in in the parietal cortex, in the visual association area. Specifically, there are often difficulties in the Angular Gyrus – an important brain “structure” that operates as a visual-verbal link.

 
The problem here is attaching the correct verbal label to the visual image that has been recorded.
Let’s go back to our bird analogy that we introduced in part 1 of this blog series.
If you have a child that looks at a goose and calls it a duck, I assert you would not think, “I think they have a visual processing problem – let’s get that boy’s eyes checked”. Rather, you would likely think “oh, they don’t know the name for a goose. There is something to teach to in that child’s language system”.
To help this child, it is likely you would feel compelled to provide a bunch of VERBAL information about ducks and geese. It might go something like this: “Honey, that is a goose. Remember, the goose is bigger, has a black head, and it says ‘honk’. That is a goose. Here is a picture of a duck. This duck has a green head. It is smaller than a goose, and it says ‘quack’, and it is called a duck”.
Can you see that what differentiates duck from goose is verbal or language-based information? The concept of “duck” and “goose” exists in the language meaning part of the brain, even though it draws from a visual description of the bird as well as a description of the sound it makes.

 
It goes the same way for letters. This is “b”, it is a stick with a bump that faces or orients to the right, it says “buh”, and we hear it in words like “bed” and “bear”. This is “d”, it is a stick with a bump that orients or faces to the left, it says “duh”, and we hear it in words like “duck” and “dad”. The difference between “b” and “d” exists in our representational language concept of each letter.
We can examine what the research says: a cleverly designed study asked children to copy some random “shapes”. These “shapes” were actually letters – but they were not CALLED letters; they were called shapes. This bit of trickery deceived the brain from activating any letter-related meaning or knowledge in the language system. Therefore, the brain used the visual processing system to copy the “shapes”. The children were quite good at this.

 

 

Then, those children were asked to copy some LETTERS. They were shown the SAME SHAPES. However, now as they children tried to re-create these shapes, their efforts were influenced by the activation of their language CONCEPT about those letters. Calling them “letters” retrieved stored experience of letters. Rather than the visual processing doing the lion’s share of the work to copy, now the language meaning processing part of the brain was contributing its 2 cents about how letters should look. This is where the confusion entered – language information stored around the concept or label of “b” and “d” was confused, and as such some of the children demonstrated reversals on some of the letters during the 2nd portion of the research task. The takeaway? The children could copy letter “shapes” using the visual processing system, but showed confusion and disorganizing during the same tasks when the label “letters” was introduced, which activated the language system.

 
The language concept of “letter” was where the breakdown occurred. Letter reversals were proven to be a language-based deficit or problem.
To complete our metaphor, if you see a goose and call it a duck (or vice-versa), there is likely a problem with your language system – not your visual system.

 
Summary
Addressing reversals requires explicit instruction in distinguishing each individual letter from the others. This is done through activities that facilitate letter concepts (refer to part 1 of this blog series for a refresher on what I mean by letter concepts).
Differentiating the sounds that letters make is an effective strategy; however, this ability is muted in children with sound processing difficulties; and often, these are the children that demonstrate reversals beyond when we might expect them to extinguish or resolve. That is one of the reasons that letter reversals beyond the mid-point of Gr. 1 are a red flag for reading difficulty).
Best practise instruction allows children to explore letters in activities that integrate processing of visual, language meaning, and sound processing simultaneously during functional literacy-based tasks.
As letter reversals resolve, children can process literacy tasks more accurately and more efficiently. This leads to improved sound-symbol correspondence, activation of the Alphabetic principle, increased word recognition, reading accuracy, reading fluency, comprehension, and accurate spelling. As such, getting reversals addressed is a worthwhile endeavour – just be sure to do so with integrated instruction during functional literacy tasks!