Dyslexia and developmental language disorder: same or different? (2023)

Most people view spoken language as a given and written language as something which requires teaching. It follows from this view that dyslexia (a disorder of written language) is separate from developmental language disorder (DLD), a disorder that affects language acquisition. But are these two fairly common childhood disorders really separate? Is one an earlier version of the other? Is one a more severe version of the other? Do they co-occur? These are questions which researchers in the field of communication disorders have grappled with, and the answers are more than ever, relevant for clinical practice.

The term ‘developmental language disorder’

According to the classification system used in clinical circles (DSM5), language disorder and dyslexia are both ‘neurodevelopmental disorders’ meaning that they are likely to be heritable, emerge early in development and persist across the life-span. It is therefore important to provide intervention, which will reduce their impact – it isn’t the case that children will ‘grow out’ of them. A major obstacle, however, is a lack of agreement as to how to identify and remediate these problems, not least because of confusion over definitions and terminology.

First, neither disorder is a ‘category’; rather these are dimensional disorders, ranging from mild to severe with no clear cut-off between ‘typical’ and ‘impaired’ in either language or reading. Moreover, while ‘diagnosis’ used to depend upon there being a discrepancy between IQ and level of attainment, there is a lack of evidence for the relevance of such exclusionary criteria and hence, they are no longer used.

Furthermore, labels abound: in DSM5, the term language disorder is used to refer to children who have very often been labelled as having ‘specific language impairment’. However, a consensus among professionals proposes that the term ‘Developmental Language Disorder’ better captures the nature and characteristics of this problem (https://doi.org/10.7287/peerj.preprints.2484v1). Dyslexia, on the other hand, is considered one of the subtypes of specific learning disorder in DSM5 – arguably a classification, which satisfies those who still debate the term, but not those who suffer. And regrettably, still others continue to regard dyslexia as a myth!

Dyslexia and developmental language disorder: same or different? (1)

The relationship between dyslexia and developmental language disorder

In 2004, Dorothy Bishop and I published a paper which proposed that in order to understand the relationship between dyslexia and what at the time was referred to as SLI (‘specific language impairment’, now DLD, ‘developmental language disorder’), it was important to consider two aspects of spoken language. First, phonological language skills, as measured by tasks such as nonword repetition. The core of learning to read is phonology and children with dyslexia and most children with DLD have phonological difficulties. Second, broader oral language skills, including vocabulary and grammar, which are components of reading comprehension.

Dyslexia and developmental language disorder: same or different? (2)

(Video) Longitudinal Relationships Between Developmental Language Disorder and Dyslexia: Same or Different?

This model has been tested by several researchers. Although it was known at the time, we did not stress enough the importance of timing. Many studies now agree that an important indicator of how well children will read is the status of their oral language system at the point at which reading instruction begins (around age 4-5 years). So, if a child has been slow to speak and language milestones are delayed, a key issue is whether they still have language problems when they enter school or whether these have resolved.

For children with persistent language difficulties, reading problems are highly likely to ensue. But also among these children is a group who can learn to decode print but have significant problems in understanding what they read. These children, called ‘poor comprehenders’ are vulnerable to failure because their reading problems go unnoticed and they often have very good memory skills which can mask the extent of their difficulties. In the model below, children with DLD are on the left of the figure – some have dyslexia, some do not, but all have reading comprehension problems.

Dyslexia and developmental language disorder: same or different? (3)

Going forward: understanding developmental pathways

A critical issue for researchers is how, at an early stage, to differentiate between children at risk of DLD whose language difficulties are likely to persist. Also, it is also important to be able to identify early, those who are vulnerable to dyslexia and those who will learn to decode well. But there is no room for complacency. Even when reading gets off to a good start, children can succumb to dyslexia at a later stage, and many children with DLD cannot read for meaning. There is still a way to go before these developmental pathways are understood; however findings from our longitudinal studies suggest that, among children with preschool language difficulties, those whose problems persist have more severe difficulties, and also additional co-occurring problems, for example in attention and motor skills.

Dyslexia and developmental language disorder: same or different? (4)

Conclusions

Maximizing children’s potential in the Early Years is a government priority yet policy makers have been slow to emphasize the importance of oral language as a springboard for learning. It is nonetheless crucial for clinicians to be monitoring the progress over time of a child who presents with poor language in the preschool years. Interventions in the Early Years should maximize the possibility of strengthening the oral foundations for literacy – not just reading readiness but also vocabulary and narrative skills. On the other hand, teachers and practitioners who work with children with dyslexia should recognize it is a language learning disorder and ensure language skills beyond phonology are considered both in assessment and intervention.

Dyslexia and developmental language disorder: same or different? (5)

(Video) What difference does having a diagnosis of Developmental Language Disorder make?

Dyslexia and developmental language disorder: same or different? (6)

Conflict of interest statement

The author is describing research which she has conducted or been involved with but has aimed to provide a consensus based on the wider literature in the field. The author is a co-author of the Nuffield Early Language Intervention Programme but has no financial interest in its publication. The Wellcome Language and Reading Project was funded by the Wellcome Trust (Grant number WT082032MA).

The views expressed are those of the author.

Links

Primary papers

Bishop, D.V.M. & Snowling, M. J. (2004). Developmental Dyslexia and Specific Language Impairment: Same or Different? Psychological Bulletin, 130, 858–888. doi: 10.1037/0033-2909.130.6.858

Fricke, S. Burgoyne, K., Bowyer-Crane, C., Kyriacou, M., Zosimidou, A., Maxwell, L., Lervag, A. O., Snowling, M. J. & Hulme, C. (2017) The efficacy of early language intervention in mainstream school settings: A Randomised Controlled Trial. Journal of Child Psychology & Psychiatry. doi:10.1111/jcpp.12737

Other references

Bishop D. V., Snowling M. J., Thompson P. A., Greenhalgh T., CATALISE-2 consortium (2017) CATALISE: a multinational and multidisciplinary Delphi consensus study of problems with language development. Phase 2. Terminology. Journal of Child Psychology & Psychiatry. DOI: 10.1111/jcpp.12721

(Video) Word Learning in Children with DLD & Dyslexia

Catts, H. W., Adlof, S., M., Hogan, T. P., & Weismer, S. E. (2005). Are Specific Language Impairment and Dyslexia Distinct Disorders? Journal of Speech, Language, and Hearing Research, 48 (6), 1378–1396. http://dx.doi.org/10.1044/1092-4388(2005/096)

Diagnostic and Statistical Manual of Mental Disorders (5th edition) DSM-5 (2013). American Psychiatric Association

Elliott, J. G. & Grigorenko, E. L.,The Dyslexia Debate (2014). Cambridge: CUP

Fricke, S., Bowyer-Crane, C., Haley, A., Hulme, C., & Snowling, M. J. (2013) Efficacy of language intervention in the early years. Journal of Child Psychology & Psychiatry, 54, 280–290. doi:10.1111/jcpp.12010

Ramus, F., Marshall, C. R., Rosen, S., & van der Lely, H. K. J. (2013). Phonological deficits in specific language impairment and developmental dyslexia: Towards a multidimensional model. Brain: A Journal of Neurology, 136, 630–645. http://dx.doi.org/10.1093/brain/aws356

Snowling, M. J. & Hulme, C (2012) Interventions for Children’s Language and Literacy Difficulties. International Journal of Disorders of Language & Communication, 47(1), 27–34. doi: 10.1111/j.1460-6984.2011.00081

(Video) Are reading and language disorders the same or different?

Snowling, M. J. & Hulme, C. (2012) The Nature and Classification of Reading Disorders: A Commentary on Proposals for DSM-5. Journal of Child Psychology & Psychiatry, 53(5), 593–607. doi: 10.1111/j.1469–7610.2011.02495.x

Other Links

Centre for Reading & Language @Oxford

Nuffield Early Language Intervention – Education Endowment Foundation

Nuffield Early Language Intervention – Nuffield Foundation

History of Dyslexia

ReadOxford

(Video) SEN Legal Webinars - Autism Spectrum Disorder vs Developmental Language Disorder

TES Article

FAQs

Is developmental language disorder the same as dyslexia? ›

Most people view spoken language as a given and written language as something which requires teaching. It follows from this view that dyslexia (a disorder of written language) is separate from developmental language disorder (DLD), a disorder that affects language acquisition.

How is DLD different from dyslexia? ›

This paper aims to integrate research on DLD and dyslexia as well as to promote the need of considering both disorders together in the future. What they found: DLD and dyslexia are related to reading comprehension in different ways. DLD influences language comprehension, while dyslexia influences word reading.

Is dyslexia a type of DLD? ›

Subsequent studies have broadly confirmed that dyslexia and DLD are separate disorders but comorbidity between them is common (Bishop, McDonald, Bird, & Hayiou-Thomas, 2009; Ramus, Marshall, Rosen, and van der Lely, 2013; Snowling, Nash, Gooch, Hayiou-Thomas & Hulme, 2019).

Is dyslexia considered a developmental disorder? ›

The International Dyslexia Association refers to dyslexia as a language-based learning disability “that does not arise from a physical limitation or a developmental disability.” To repeat: Dyslexia is NOT a developmental disability.

What type of language disorder is dyslexia? ›

In a 1989 article entitled “Defining Dyslexia as a Language Based Disorder,” Hugh Catts stated, “Dyslexia is a developmental language disorder that involves a deficit(s) in phonological processing.

Can Language Disorders be dyslexic? ›

dyslexia and DLD frequently co-occur, although no one knows exactly how often (different studies, with different designs, show a 17-71% co-occurrence!);

At what age is DLD diagnosed? ›

Children with DLD are often as clever as any other child of their age but they still have difficulties with speech and language. Children are not usually diagnosed until after the age of 5 and until some therapy has been carried out to see if the difficulties resolve.

What are the four types of dyslexia? ›

Dyslexia can be developmental (genetic) or acquired (resulting from a traumatic brain injury or disease), and there are several types of Dyslexia including phonological dyslexia, rapid naming dyslexia, double deficit dyslexia, surface dyslexia, and visual dyslexia.

Do children with DLD have normal intelligence? ›

Developmental Language Disorder (DLD) is characterized by the absence of speech in children despite their normal non-verbal IQ, no primary physical disabilities, neurological disorder or mental illness (Leonard, 2008; Reilly et al., 2014; Bishop et al., 2016, 2017).

What is the difference between dyslexia and developmental dyslexia? ›

Use of the term primarily distinguishes between genetic and acquired forms of dyslexia. Acquired forms typically result from stroke or head trauma for example, they present very differently and can diminish over time, whereas developmental dyslexia is a life long condition.

What is developmental language disorder? ›

What is Developmental Language Disorder? Developmental Language Disorder (DLD) means that you have significant, on-going difficulties understanding and/or using spoken language, in all the languages you use. DLD was previously known as Specific Language Impairment (SLI).

What are the 7 types of dyslexia? ›

Are There Different Kinds of Dyslexia?
  • dysphonetic dyslexia.
  • auditory dyslexia.
  • dyseidetic dyslexia.
  • visual dyslexia.
  • double deficit dyslexia.
  • attentional dyslexia.

Why is it called developmental dyslexia? ›

The term developmental dyslexia ("specific reading retardation") refers to an unexpected difficulty in reading in children and adults who otherwise possess the intelligence, motivation, and schooling considered necessary for accurate and fluent reading.

What are the signs of developmental language disorder? ›

Children with DLD may:
  • struggle to find the words to express ideas.
  • have trouble organising sentences, having conversations or telling a story.
  • find it hard to understand words, follow instructions or answer questions.
  • not remember what someone has said.
  • have difficulty paying attention.
  • have difficulty reading and writing.
13 Jul 2021

What are the two types of language disorders? ›

There are 2 kinds of language disorders: receptive and expressive. Children often have both at the same time. A child with a receptive language disorder has trouble understanding words that they hear and read.

How does dyslexia affect language development? ›

But dyslexia may affect a child's speech as well, due to difficulties with language processing. A child with dyslexia may struggle with poor word retrieval. This means that they may know a word but have difficulties remembering how it sounds. Children with dyslexia often exhibit a slower acquisition of language skills.

What are the names of language disorders? ›

10 Common Types of Speech Disorders
  • Childhood Apraxia of Speech. ...
  • Orofacial Myofunctional Disorders. ...
  • Speech Sound Disorders/Articulation Disorders. ...
  • Stuttering and Other Fluency Disorders. ...
  • Receptive Disorders. ...
  • Autism-Related Speech Disorders. ...
  • Resonance Disorders. ...
  • Selective Mutism.
11 Dec 2019

Is there dyslexia for speaking? ›

It's not surprising that people with dyslexia have trouble spelling. They also might have trouble expressing themselves in writing and even speaking. Dyslexia is a language processing disorder, so it can affect all forms of language, spoken or written.

Can a child grow out of DLD? ›

DLD is a developmental disorder, which means that its symptoms first appear in childhood. This does not mean that, as children develop, they grow out of the problem. Instead, the condition is apparent in early childhood and will likely continue, but change, as they get older.

Is DLD life long? ›

As DLD is a lifelong condition, people may access speech and language therapy services at different times during their life if appropriate.

Is there a cure for DLD? ›

While there is no cure, support is available to help children with DLD develop skills and strategies to achieve their potential. Your speech-language pathologist will conduct an assessment which includes taking a history of your child's development and noting any health concerns.

What are the main signs of dyslexia? ›

confusion over letters that look similar and putting letters the wrong way round (such as writing "b" instead of "d") confusing the order of letters in words. reading slowly or making errors when reading aloud. answering questions well orally, but having difficulty writing the answer down.

What is the new term for dyslexia? ›

There are various reasons why individuals struggle with developing literacy skills; dyslexia is but one of those reasons. Some suggest that the term dyslexia be discarded and that the term reading disability be used in its stead. If it is redefined as such, and the terms are synonymous—I agree.

How can you identify dyslexia? ›

Reading
  1. Slow reading progress.
  2. Finds it difficult to blend letters together.
  3. Has difficulty in establishing syllable division or knowing the beginnings and endings of words.
  4. Unusual pronunciation of words.
  5. No expression in reading, and poor comprehension.
  6. Hesitant and laboured reading, especially when reading aloud.

Is DLD a disability? ›

Developmental Language Disorder is when a child or adult has difficulties talking and/or understanding language. DLD is a hidden disability that affects approximately two children in every classroom, affecting literacy, learning, friendships and emotional well-being.

Is DLD a neurological disorder? ›

Developmental language disorder (DLD) is a neurodevelopmental condition that emerges in early childhood and frequently persists into adulthood. People with DLD have significant difficulty learning, understanding, and using spoken language.

Is developmental language disorder permanent? ›

DLD is a lifelong condition and while targeted interventions and speech-language pathology support is important, teachers have a critical role in identifying and addressing language-based barriers within the school environment.

Can dyslexia cause developmental delays? ›

Slow Development of Fine Motor Skills

Fine motor skills may be slow to develop in children with dyslexia. For example, WebMD says they “may take longer than others of the same age to learn how to hold a pencil in the writing position, use buttons and zippers, and brush his or her teeth.”

Is dyslexia the same as autism? ›

People often confuse dyslexia and autism for one another or conflate them for their similarities. But they are two completely different disorders that affect the brains of people in different ways. While dyslexia is a learning difficulty, autism is a developmental disorder.

What are 5 characteristics of dyslexia? ›

Some common characteristics that can indicate dyslexia include:
  • Skill levels lower than individual's intellect.
  • Inconsistent IQ tests.
  • Language processing difficulties.
  • Poor oral reading skills.
  • Poor reading comprehension.
  • Inconsistent listening comprehension.
  • Literal interpretation of language.

What are the three types of language disorders? ›

three types of language disorders
  • Phonology, or speech sounds and patterns. ...
  • Morphology, or how words are formed. ...
  • Syntax, or the formation of phrases and clauses.

Is DLD a special need? ›

DLD is a brain difference that makes talking and listening difficult. DLD affects about 2 children out of every classroom. DLD is associated with risk for dyslexia and other learning disabilities.

What are the different types of developmental disorders? ›

Child Development Specific Conditions
  • Anxiety.
  • Attention-Deficit/Hyperactivity Disorder (ADHD)
  • Autism Spectrum Disorders.
  • Cerebral Palsy.
  • Conduct Disorder (CD)
  • Depression.
  • Developmental Disabilities.
  • Fetal Alcohol Spectrum Disorders.

What are three signs of dyslexia? ›

Grades 3–5 signs of dyslexia
  • Confusing or skipping small words like for and of when reading aloud.
  • Having trouble sounding out new words.
  • Having trouble quickly recognizing common words (also called sight words)
  • Struggling to explain what happened in a story or answer questions about key details.

Is dyslexia an eye or brain problem? ›

Dyslexia is considered a primary reading disorder and results from language processing (written word processing) abnormalities in the brain. Children learning to read experience difficulties with sight word recognition, poor spelling and decoding deficits.

What is the opposite of dyslexia? ›

Hyperlexia can be the opposite of dyslexia, a learning disability characterized by having difficulty reading and spelling. However, unlike children with hyperlexia, dyslexic children can normally understand what they are reading and have good communication skills.

Why is it called a developmental disorder? ›

Developmental disabilities are a group of conditions due to an impairment in physical, learning, language, or behavior areas. These conditions begin during the developmental period, may impact day-to-day functioning, and usually last throughout a person's lifetime.

What is the best definition of dyslexia? ›

Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities.

Is DLD a form of autism? ›

Developmental language disorders (DLD)

In DLD, language deficits occur in the absence of a known biomedical condition, such as autism spectrum disorder or Down syndrome, and interfere with the child's ability to communicate effectively with other people.

What is the difference between SLI and DLD? ›

Developmental language disorder (DLD, also called specific language impairment, SLI) is a common developmental disorder comprising the largest disability group in pre-school-aged children. Approximately 7% of the population is expected to have developmental language difficulties.

Can you have mild DLD? ›

Because DLD is a spectrum disorder, it can sometimes be difficult to diagnose. There will be borderline cases where the child's problems are mild, and we are not sure if a clinical diagnosis is warranted.

Is dyslexia and developmental dyslexia the same? ›

Developmental dyslexia is not so much a type of dyslexia, it is dyslexia. In fact the definition of it would be the same as our definition of dyslexia generally: Extreme difficulty reading caused by a hereditary, brain based, phonologic disability.

What are developmental language disorders? ›

Developmental language disorder (DLD) is a communication disorder that interferes with learning, understanding, and using language. These language difficulties are not explained by other conditions, such as hearing loss or autism, or by extenuating circumstances, such as lack of exposure to language.

What disorders are similar to dyslexia? ›

Some students with dyslexia also have Attention-Deficit Hyperactivity Disorder (ADHD), dysgraphia, dyscalculia, speech/language disorders, executive functioning disorder, and/or anxiety. A description of the most common conditions to accompany dyslexia are described in the text that follows.

What is DLD caused by? ›

There is no known cause of DLD and that can make it hard to explain. DLD is not caused by emotional difficulties or limited exposure to language. DLD is not caused by other medical conditions such as hearing loss, physical impairment, Autism, severe learning difficulties, or brain injuries.

What are the early signs of DLD? ›

Signs of DLD By Age​
  • Sentences that are short and not grammatical in his or her dialect. For example: Car go. Me happy. Him running. ...
  • Difficulty following directions when not embedded in a routine.
  • Difficulty understanding what is being said.
  • Difficulty asking questions.
  • Difficulty finding words to express thoughts.
18 Jul 2022

Are people born with DLD? ›

There is no simple reason why some people have DLD and find language tricky. Researchers think it is partly something people are born with. How we grow up and the different ways our brains develop might also play a part. DLD is not caused by other conditions like autism or brain injury.

Is DLD a lifelong condition? ›

As DLD is a lifelong condition, people may access speech and language therapy services at different times during their life if appropriate.

What are the 4 types of dyslexia? ›

Dyslexia can be developmental (genetic) or acquired (resulting from a traumatic brain injury or disease), and there are several types of Dyslexia including phonological dyslexia, rapid naming dyslexia, double deficit dyslexia, surface dyslexia, and visual dyslexia.

What disorder is the opposite of dyslexia? ›

Hyperlexia can be the opposite of dyslexia, a learning disability characterized by having difficulty reading and spelling. However, unlike children with hyperlexia, dyslexic children can normally understand what they are reading and have good communication skills.

Is dyslexia a form of autism? ›

People often confuse dyslexia and autism for one another or conflate them for their similarities. But they are two completely different disorders that affect the brains of people in different ways. While dyslexia is a learning difficulty, autism is a developmental disorder.

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