The instruction was simple: “Take out your notebooks and write down today’s date.” Yet, in the classroom, one student sits motionless, staring at the blank page. The teacher thinks to himself that, once again, the child hasn’t been listening—that he has his “head in the clouds” yet again.
He doesn’t see the tremendous effort this student is putting in: right from the start of the day, the child has had to muster all his energy to decode sounds, put words together, and make sense of them. While the others have already started writing, he’s still just trying to figure out what’s being asked of him. This child lives with an invisible disorder: developmental language disorder (DLD).
Formerly known as “dysphasia” or “specific oral language disorder,” SLI is classified as a neurodevelopmental disorder. These disorders emerge early in development and have a lasting impact on personal, social, academic, and occupational functioning throughout life (DSM-5). Here’s what you need to know about SLI.
Language Difficulties
The acquisition and development of spoken language occur very rapidly: by the age of five, a child is capable of initiating and sustaining a conversation similar to that of an adult, even though he or she still cannot tie his or her shoes. Behind this seemingly effortless learning process lies one of the most complex functions of the human brain. This complexity becomes particularly evident when developmental disruptions occur, as is the case with TDL.
SLI is generally diagnosed when a child exhibits significant and persistent difficulties in understanding or producing language, with functional implications in daily life. In addition, the children affected have had adequate language exposure and do not have any biomedical conditions (i.e., no sensory, neurological, or intellectual impairments) that would explain these difficulties.
The language difficulties experienced by children with SLI can vary widely. They may involve the production of speech sounds, vocabulary use, sentence structure, the application of grammatical rules, the ability to tell a story, adherence to rules of communication and conversation, the memorization of verbal information, or the comprehension of words and instructions.
It is important to note that these manifestations vary greatly from one individual to another. Furthermore, as language evolves with age, the difficulties change over the course of development. Thus, the manifestations of SLI differ not only from one person to another, but they can also change in the same person over time.
In any case, these language difficulties have a significant impact on the child’s daily life—whether at home, in learning, in relationships with peers, or in terms of self-esteem.
Misunderstood Causes
TDL is estimated to affect 7.5% of the population, or about 2 children per classroom, which represents approximately 50,000 births per year and nearly 5 million people in France. By comparison, autism spectrum disorder, which is better known to the general public, affects about 1 to 2% of the population, or about 15,000 new cases among newborns each year in France.
The causes of TDL are not fully understood. It is a multifactorial disorder resulting from the interaction of genetic, biological, and environmental factors. To date, no single gene has been identified as responsible for TDL. However, a hereditary component is well established: the risk of developing this disorder is higher when other family members are affected.
Certain early biological or environmental factors have also been linked to an increased risk of language difficulties, although they are not considered direct causes of SLI. Examples include prematurity, low birth weight, and other perinatal complications.
Research also shows that a low socioeconomic status or a lack of stimulation (such as when parents speak little to their child, for example) are risk factors for language disorders; conversely, living in a language-rich environment (reading books to children, engaging in language-stimulating activities, and participating in high-quality and varied social situations) serves as a protective factor, promoting language development in all children, though it does not, on its own, prevent the onset of a language disorder.
It is important to emphasize that bilingualism—or, more broadly, exposure to multiple languages—does not cause language delay. Children are capable of learning multiple languages from early childhood onward.
At present, no specific biological, neurological, or environmental marker can, on its own, explain or confirm the presence of the disorder, nor can it predict its onset with certainty.
Difficulties that begin very early and persist
It is often difficult to diagnose SLI before the age of 3 or 4, as transient language difficulties can resemble those associated with SLI. However, persistent difficulties with language comprehension or production between 18 months and 5 years of age are associated with an increased risk of SLI.
Efforts to clarify and disseminate information about TDL have become significantly more structured in recent years. A major turning point was the establishment of the CATALISE international consensus, which emerged from a multidisciplinary panel of 59 international experts and was coordinated by several researchers and clinicians, including British psychologist Dorothy Bishop.
Among the recommendations, the term “developmental language disorder” is recommended when language difficulties persist beyond preschool (after age six) and result in a significant functional impact on daily life, without any environmental or biomedical factors that could explain this atypical development.
By standardizing terminology and identification criteria, this consensus provides a common framework for scientific research, thereby facilitating the gradual collection of scientific data and its comparison. Milestones related to the development of communication, language, and speech were also discussed as part of this consensus.
In fact, signs of atypical language development in children can be cause for concern. These signs vary depending on the child’s age (for more information on these warning signs, visit the allo-ortho website ).
By age five, if difficulties are still present, it is likely that they will persist. Therefore, if there are any concerns about a child’s language development, it is important to address them immediately.
During childhood, it is often learning difficulties that raise concerns. Children with SLD are six times more likely to experience difficulties with written language, four times more likely to have difficulties with mathematics, and up to twelve times more likely to experience all of these difficulties.
Beyond academic challenges, the consequences of TDL extend to the psychosocial realm. These children are more prone to anxiety, depression, and behavioral disorders.
Difficulties That Persist into Adulthood
The vulnerabilities affecting children with SLI also tend to persist into adulthood. They result in difficulties with employment, psychological well-being, and social life.
To date, there has been limited research on the experiences of adults with TDL. In 2024, a study was conducted to understand how TDL impacts the daily lives of adults throughout their lives. The researchers gathered the perspectives of adults living with this disorder in the United Kingdom. The results revealed that this disorder has a lasting impact on the lives of adults who have it.
In particular, they feel excluded and have difficulty following conversations, which can lead to feelings of loneliness, isolation, and anxiety. In the workplace, they often struggle to find or keep a job due to misunderstandings, discrimination, or the fear of having to disclose their condition.
While several international studies highlight persistent vulnerabilities in academic, professional, and psychosocial areas, no large-scale study to date has documented these trajectories in France. This lack of empirical data constitutes a significant obstacle to the development of targeted, evidence-based support programs.
A Public Health Issue That Is Overlooked
TDL exhibits all the characteristics of a public health issue (prevalence, significant functional impacts on daily life). However, it remains relatively unknown to the general public and receives less attention than other neurodevelopmental disorders in research, the media, and public policy.
This lack of visibility surrounding TDL is directly evident in research. In fact, in 2020, there were only 0.03 scientific publications per 100 children with TDL in the United States. For autism spectrum disorders, for example, this ratio is 7.94. This disparity is significant and lies at the heart of major challenges concerning not only the generation of fundamental knowledge about TDL, but also the development of diagnostic tools, treatment recommendations, and the availability of funding for research and clinical care.
One of the main reasons for this invisibility is, among other things, the wide variety of diagnostic terms used in the past. SLI has been referred to by more than 30 different names: dysphasia, specific language disorder, developmental aphasia, etc. In France, the term “dysphasia” is still often preferred when referring to it among the “DYS” disorders. This wide variability in terminology still significantly hinders the characterization and management of this disorder.
It also reflects the inherent complexity of language. Indeed, another important reason for the invisibility of TDL is its “hidden” nature: language difficulties can be subtle (for example, searching for words, using filler words like “thing” or “stuff,” or using simple sentences), misinterpreted (confused with shyness or an intellectual disability), or masked by compensatory strategies, which makes it difficult to accurately identify the difficulties.
Talk More About TDL
Raising awareness of TDL will help advance research on the topic.
The knowledge gained will facilitate the implementation of methods for earlier identification and more targeted interventions. It will improve the identification of the skills that these children have retained (their strengths), as well as the protective factors that should be reinforced—such as quality social interactions and fulfilling activities that build self-esteem—which can improve their situation both during childhood and in adulthood.
Because it bears repeating: SLI may require tailored interventions throughout a person’s life, particularly during times of transition (adolescence, the transition to higher education, entering the workforce, etc.). The first step toward better care is a simple one: we need to talk more about specific language impairment!
To learn more:
Raising awareness of developmental language disorder (DLD) extends beyond the academic sphere: it is also an effort driven by those affected, their families, and professionals. The international movement “Raising Awareness of Developmental Language Disorder,” founded in 2012, is a prime example of this. Coordinated by an international volunteer committee and active in more than 40 countries, including France, this movement organizes an International DLD Awareness Day every October to bring attention to this invisible disorder.
Other resources are also available:
– Explanatory videos produced by Estelle Gillet-Perret, a speech-language pathologist at the Reference Center for Language and Learning Disorders at the Grenoble Alpes University Hospital;_
– The website of the Avenir Dysphasie TDL Franceassociation;_
– Visual aids, such as postcards and posters; _
– You can follow the latest news from the EVEIL TDL France group on Instagram (@radldfrance) and LinkedIn (RADLDFRANCE)._
– Information about the language and TDL can also be found on the websites Allo-ortho, French Dys Federation and TDL Quebec Group. _
