Marcos, a bilingual teenager growing up with two languages ​​and two distinct approaches to reading, keeps up relatively well in Spanish Language and Literature class: he reads slowly and makes some mistakes, but he understands the texts and participates without too much difficulty. In English, however, he hesitates over common words, loses his place in the text, and takes much longer than his classmates to write or decipher seemingly simple sentences. Furthermore, when asked to read aloud, he looks down even before it’s his turn.

These kinds of situations baffle many families and teachers. How can someone function relatively well in one language and experience significant difficulties in another? Can dyslexia manifest itself differently depending on the language?

Far from being anecdotal, both questions are appearing with increasing frequency in bilingual and multilingual contexts. They raise a central question for current research: to what extent do the difficulties associated with dyslexia depend not only on the brain that reads, but also on the writing system that the brain attempts to decipher?

Which languages ​​make dyslexia more visible?

The idea that a person can have dyslexia in English but not in Spanish may seem contradictory. However, current scientific evidence suggests that the difficulties associated with this learning disorder can be much more pronounced in some languages ​​than in others. Although dyslexia has a neurobiological basis—that is, it is related to how the brain processes written language—its manifestations can also vary depending on the characteristics of each language’s writing system .

This is because not all languages ​​exhibit the same degree of regularity in the relationship between letters and sounds: it is precisely this relationship that learning to read automates. In English, for example, the same groups of letters can sound very different ( drought and brought are not pronounced the same way, just as mint , lint , and hint are pronounced differently from pint ), which can increase the complexity of learning to read.

Relationship with writing

These differences affect not only reading but also how writing is learned. Neuroscientist Taeko Wydell has pointed out that in writing systems like Japanese, where learning combines motor repetition and oral pronunciation of characters, some difficulties can manifest themselves differently.

In this sense, documented cases of bilingual students who have difficulties in English, but not in Japanese, have contributed precisely to questioning the idea of ​​an identical dyslexia in all languages.

Transparent and not-so-transparent languages

Similarly, a recent study of bilingual Welsh-English adults with dyslexia showed that they exhibited a different reading profile than monolingual English speakers. The bilingual participants showed fewer difficulties in tasks related to phonological processing and reading pseudowords (invented words used to assess the processing of language sounds), likely because Welsh has a much more consistent, or transparent, orthography than English.

As a main finding, the authors concluded that learning to read simultaneously in a consistent, or transparent, language and in an inconsistent, or not so transparent, language can modify reading and writing strategies and alter the way in which difficulties associated with dyslexia manifest themselves.

In fact, current scientific reviews indicate that some difficulties, such as the speed of access to language sounds or certain alterations in reading fluency, tend to remain relatively stable across languages. However, other difficulties depend much more on the orthographic characteristics of each language, which explains why these differences may be more visible in some writing systems than in others.

When dyslexia goes unnoticed

In consistent languages ​​like Spanish (that is, languages ​​in which the sounds of letters and their combinations remain almost always regular), many people are able to read with relative accuracy from an early age. However, this apparent normality can be deceptive.

Although reading demands more time, greater concentration, and increased cognitive effort, it may seem functional from the outside. However, as has been documented for years in numerous studies , this does not mean the problem disappears. Rather, students often manage to partially compensate for these difficulties for years, which explains why some achieve good academic results and yet still experience significant reading fatigue.

However, the situation changes when these students encounter more inconsistent spellings. Several studies with bilingual individuals indicate that difficulties tend to become more apparent in languages ​​with more irregular spellings. This leads to the emergence of errors that previously seemed nonexistent, and to the development of different compensatory strategies depending on the specific spelling characteristics of each language.

Therefore, it is not surprising that some cases of dyslexia are detected precisely during the learning of a second or third language since, in reality, it does not “appear” suddenly but rather, certain linguistic characteristics simply make previous difficulties much more visible.

Languages ​​that hide versus languages ​​that reveal

Having reached this point, we can recognize that the initial question contained a misleading idea: thinking that dyslexia belongs to a specific language .

Dyslexia has a neurobiological basis related to language processing, but its manifestations also depend on the characteristics of the writing system each reader encounters. Therefore, a person may appear to be a proficient reader in Spanish and experience significant difficulties in English. This is not because they are dyslexic only in English, but because some languages ​​act like a magnifying glass , highlighting difficulties that until then remained partially hidden, while others manage to conceal them for years.

And perhaps that is one of the most important ideas that current research brings: understanding dyslexia not only involves understanding how the reading brain works, but also how it interacts with the different languages ​​it learns to decipher.

Ultimately, understanding how the brain and written language interact in each language will not only help to debunk past and future myths, but also to improve the educational response in increasingly linguistically diverse classrooms.

Author Bio: Diego Paniagua Martín is Clinical Linguist | Expert in Linguistic Competence and Disability at UNIR – International University of La Rioj