Not All Literacy Difficulties Are Dyslexia: Understanding the Difference Between Dyslexia and Developmental Language Disorder (DLD)

When a child or adult struggles with reading, spelling, or writing, many people immediately wonder: “Do I have dyslexia?” Dyslexia is widely recognised, and with growing awareness, more people are seeking dyslexia assessments and dyslexia testing.

But not all literacy difficulties are caused by dyslexia. Another condition—Developmental Language Disorder (DLD)—is just as common as dyslexia, yet it is far less well-known. Because of this, DLD is often hidden, overlooked, or misunderstood by teachers, parents, and even professionals.

Understanding the difference between dyslexia and DLD is crucial for ensuring children, students, and adults get the right support. A full private dyslexia test doesn’t just screen for dyslexia; it can also indicate whether underlying language difficulties might be affecting literacy.

What Is Dyslexia?

Dyslexia is a specific learning difference that primarily affects reading, spelling, and written expression. People with dyslexia often struggle with phonological processing (the ability to break words down into sounds), working memory, and speed of processing.

Common signs include:

• Difficulty decoding unfamiliar words

• Slow or effortful reading

• Poor spelling and inconsistent written work

• Strengths in reasoning, problem-solving, or creativity despite literacy challenges

  
  

A dyslexia assessment provides a formal dyslexia diagnosis and explains a person’s unique learning profile. This can unlock access to tailored teaching strategies, support in exams or the workplace, and greater self-understanding.

What Is Developmental Language Disorder (DLD)?

Developmental Language Disorder is a condition where individuals experience ongoing difficulties with understanding or using spoken language. Unlike dyslexia, which is primarily about reading and spelling, DLD affects broader aspects of communication.

Challenges faced by people with DLD may include:

• Struggling to understand complex sentences or spoken instructions

• Finding it hard to learn and remember new words

• Difficulty putting thoughts into words

• Limited vocabulary compared to peers

• Challenges with grammar and sentence structure

• Trouble following conversations, especially in noisy environments

• Anxiety or withdrawal in social situations due to communication difficulties

  
  

DLD often goes unnoticed because children may appear “quiet,” “shy,” or “not paying attention” rather than being seen as having a specific learning difficulty. Adults with undiagnosed DLD may avoid jobs or studies that require heavy verbal communication, without ever realising why these tasks feel harder.

How Common Is DLD?

DLD affects around 7% of the population—that’s about two children in every classroom, making it just as common as dyslexia.

Yet unlike dyslexia, which has received increasing awareness, DLD often remains hidden. Teachers and parents may notice reading difficulties but not connect them to an underlying language disorder. This means many children with DLD don’t get the support they need.

Dyslexia vs. DLD: Key Differences

Dyslexia	Developmental Language Disorder (DLD)
Primarily affects reading, spelling, and written expression	Affects understanding and use of spoken language
Rooted in phonological (sound-based) processing difficulties	Rooted in broader language processing difficulties
May have average or strong spoken language skills	Often has limited vocabulary or struggles with grammar and comprehension
Support often focuses on phonics, spelling, and reading fluency	Support often focuses on vocabulary, comprehension, and expressive language
Identified more frequently by schools and parents	Frequently overlooked or misattributed to shyness, inattention, or low motivation

Why the Difference Matters

If a child or adult is struggling with literacy, it’s important not to assume dyslexia is the only explanation. Some individuals may have dyslexia, some may have DLD, and some may experience both.

Misidentifying DLD as dyslexia alone can lead to the wrong interventions. A child with DLD may not benefit from phonics-based interventions in the same way as a child with dyslexia, because their primary challenge lies in understanding and using language, not just decoding words.

That’s why a thorough dyslexia assessment is so important.

How a Full Dyslexia Assessment Helps

A professional dyslexia assessor doesn’t just look at reading and spelling. A high-quality dyslexia assessment explores a range of skills, including:

• Phonological processing

• Working memory

• Reading fluency

• Writing and spelling

• Oral language abilities

  
  

If the assessment suggests that difficulties extend beyond phonological skills into language comprehension and expression, this can point towards potential language difficulties such as DLD.

While a dyslexia assessor cannot formally diagnose DLD (this is typically carried out by a speech and language therapist), a detailed assessment report can flag the need for further investigation. This ensures individuals don’t “slip through the cracks” with hidden DLD.

Why DLD Is Often Missed

Unlike dyslexia, which tends to become clear when children learn to read, DLD can be masked by coping strategies. Children may stay quiet in class, memorise words without truly understanding them, or avoid situations where their language difficulties might show.

Adults with undiagnosed DLD may:

• Avoid public speaking or group discussions

• Struggle with job interviews or professional training

• Experience frustration in social communication

• Develop anxiety or low confidence due to feeling “different”

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Because these signs are less obvious than spelling mistakes or slow reading, DLD can remain hidden for years.

FAQs

How do I know if my child has dyslexia or DLD

A full dyslexia assessment for children can highlight whether literacy challenges are linked to phonological difficulties (more typical of dyslexia) or broader language difficulties (which may indicate DLD).

Can adults have DLD without knowing it?

Yes. Just as adults can go through dyslexia assessments for adults, many discover later in life that undiagnosed DLD has been affecting their communication and confidence for years.

Do online dyslexia tests pick up DLD?

Free dyslexia tests online or quick dyslexia screenings online cannot reliably identify DLD. Only a full, professional private dyslexia test can provide insights into whether language difficulties may also be present.

Why does it matter if it’s dyslexia or DLD?

The right diagnosis leads to the right support. Dyslexia interventions often focus on phonics and reading strategies, while DLD support may involve vocabulary development, comprehension support, and speech and language therapy.

Final Thoughts

Not all literacy difficulties are dyslexia. Developmental Language Disorder is just as common but often goes unnoticed because it is less well understood. While dyslexia primarily affects reading and spelling, DLD impacts understanding and using spoken language, often leading to hidden struggles in school, work, and everyday life.

A full dyslexia assessment can provide clarity—not only confirming whether someone has dyslexia but also highlighting whether broader language difficulties may be contributing to their challenges. This is the first step in ensuring individuals get the right support, strategies, and accommodations to thrive.

If you’re wondering, “Do I have dyslexia?” or concerned about a child’s reading, writing and communication skills, the best way forward is testing for dyslexia with a qualified dyslexia assessor such as Chrissy at Lexety Education. Whether you’re looking for dyslexia assessments for adults, students, or children, Lexety provides thorough, supportive testing that can guide you towards the right help. Book a free consultation call to find out if dyslexia assessment is the right option for you.