Reading Comprehension Isn’t Just About Reading: 6 Hidden Causes of Difficulty

Why some children read the words perfectly… but still struggle to understand the text.

Many parents tell me the same thing: “She can read beautifully, but when I ask her what it means, she hasn’t got a clue.”

It’s a common worry and an incredibly frustrating experience for children who can sound fluent but struggle to make sense of what they’ve read.

The truth is this: Reading comprehension is not a single skill. It’s a whole network of abilities working together at the same time. When even one of those underlying skills is fragile, a child’s understanding can suddenly feel patchy, inconsistent, or surprisingly weak compared to their verbal ability.

Here are six often-overlooked reasons why children and teens may struggle with comprehension, even when their reading seems fine on the surface.

1. Cognitive Load: Decoding Uses Up All Their Brain Space

If a child is working hard to decode unfamiliar or irregular words, their brain is already under strain. And when decoding takes up too much cognitive space, there’s simply not enough left over for meaning-making.

Even children who “read quickly” can be masking effortful, inconsistent decoding that drains the cognitive resources needed for deep understanding.

2. Working Memory Limitations

Reading comprehension relies heavily on working memory — the ability to hold and manipulate information in the mind.

A child with weaker working memory may:

• forget what happened at the beginning of the sentence

• lose track of the storyline

• struggle to hold multiple ideas at once

• find inference or prediction particularly challenging

  
  

They may understand each sentence, but lose the thread when they try to connect them.

3. Slow Reading Fluency (Even if They’re Accurate)

Reading fluency isn’t just speed, it’s a balance of accuracy, pace, and expression. Children who read accurately but slowly often struggle with comprehension because:

• the text takes too long to process

• ideas feel disjointed

• they can’t maintain momentum

• meaning fades before they reach the end

  
  

Fluency acts as a bridge between decoding and understanding. When it isn’t automatic, comprehension suffers.

4. Limited Vocabulary (Especially Academic Vocabulary)

By age 13, vocabulary differences become one of the strongest predictors of comprehension.

A child might read every word correctly but still miss the meaning because:

• the vocabulary is unfamiliar

• they don’t understand figurative or nuanced language

• subject-specific terms (e.g., “evaluate”, “infer”, “justify”) get in the way

  
  

This is particularly noticeable in exam-style texts where “everyday reading ability” isn’t enough.

5. Weak Background Knowledge

Comprehension depends on what a reader already knows. If a text assumes familiarity with a topic (climate change, medieval history, electrical circuits) a child may struggle, even if their reading skills are solid.

A lack of background knowledge creates gaps that make comprehension harder, slower, and more effortful.

6. Fatigue and Effort

This one is rarely talked about, but hugely important.

Many children with undiagnosed dyslexia or literacy difficulties read with high levels of mental effort. They can appear fine for the first few paragraphs, but:

• their accuracy drops

• they lose focus

• they forget what they’ve read

• comprehension collapses

• they feel frustrated or overwhelmed

  
  

Fatigue can explain why a child seems to understand short texts but not longer ones — or why comprehension varies from day to day.

What This Means for Parents

If your child struggles with comprehension, it does not mean they’re lazy or inattentive and it doesn’t always point to a single cause.

Often, comprehension difficulties are a symptom of a deeper issue:

• decoding that isn’t fully automatic

• working memory challenges

• reduced fluency

• gaps in vocabulary

• difficulty sustaining effort

• or a combination of several

  
  

A thorough learning assessment can help identify which underlying skills are responsible, so support can be targeted and effective.

If You’re Concerned About Your Child’s Reading

I offer specialist assessments for children and teens, designed to help you understand why your child is struggling and what will help them move forward.

You can book a free 30-minute enquiry call here: https://lizzymorton.youcanbook.me/