Dyslexia is a specific language impairment (SLI) that affects the ability to read and write accurately and fluently. It falls into two main categories: developmental dyslexia and acquired dyslexia.
Developmental dyslexia emerges in childhood and is linked to neurological differences in the brain areas responsible for language processing. Recent studies have shown that individuals with a genetic predisposition to dyslexia exhibit specific structural differences in the brain, such as reduced nerve fibre density in the internal capsule and a smaller motor cortex volume. These differences are associated with lower performance in reading and language skills.
In contrast, acquired dyslexia occurs when a person, with no previous reading difficulties, sustains brain damage that impairs their ability to read and write. This type of dyslexia can result from strokes, traumatic brain injuries, or other neurological conditions that affect the language-processing regions of the brain.
The impact of dyslexia varies depending on the language. In opaque languages like English, where the relationship between letters and sounds is inconsistent, individuals with dyslexia face greater challenges in decoding words. For example, a single grapheme can have multiple pronunciations, making reading acquisition more complex. Consider words like “through” and “though”, which have similar spellings but very different pronunciations—an inconsistency that complicates learning. This phonological unpredictability contributes to a higher prevalence of dyslexia in speakers of opaque languages
By contrast, in transparent languages like Spanish, where there is a more direct correspondence between graphemes and phonemes, dyslexia presents differently. While difficulties persist, the predictable orthographic structure facilitates decoding, potentially reducing certain common reading errors.
Understanding these differences is essential for tailoring educational and therapeutic strategies to the language and type of dyslexia, ensuring better support for those affected. Recent treatments include eye-tracking-assisted reading tools, as well as virtual reality applications integrated with artificial intelligence (AI) to personalise educational support.
Óscar Fernández García.
Valladolid, 5th March 2025.
