New to this topic? Start with our companion article: Phonological Processing vs Articulation: What's the Difference? | Brisbane Speech Pathologist
Speech and reading can look like completely different skills. One happens with the mouth, the other with the eyes; one starts in toddlerhood, the other in Prep. Most families think of them as separate concerns handled by separate professionals. But in the research — and in the families we support — they're so deeply intertwined that it's almost impossible to talk about one without the other.
This article is the "so what?" of the speech sound cluster. We've covered what delayed, atypical, and disordered speech patterns look like, and why phonological and articulation difficulties need different therapy. Here we tackle a different question: why does any of this matter once your child starts school? The short answer is that unresolved speech sound difficulties can follow a child straight into the literacy curriculum — and the research on that connection is some of the most consistent in our field.
The Connection Between Speech Sounds and Literacy
Here's the key idea: reading isn't just a visual skill. When children learn to read, they need to map written letters onto the sounds of their language. To do that, they first need a solid understanding of those sounds — what they are, how they differ from each other, and how they combine to make words.
This skill is called phonological processing, and it's the bridge between spoken language and written language.
When a child has phonological processing difficulties — where they mix up, simplify, or substitute groups of sounds in predictable patterns — it can signal that their internal "map" of the sound system isn't fully developed. And if that map is fuzzy for speech, it's often fuzzy for reading too.
The Simple View of Reading
One of the most widely used frameworks for understanding reading is the Simple View of Reading, developed by Gough and Tunmer. It says that reading comprehension is the product of two things:
Reading Comprehension = Decoding × Language Comprehension
- Decoding is the ability to read words accurately — sounding them out, recognising them
- Language comprehension is the ability to understand the meaning of what's been read
Both matter. A child who can decode words but doesn't understand them won't comprehend what they've read. And a child who understands language well but can't decode the words on the page will struggle just the same.
Here's where speech sound difficulties come in: they can affect both sides of this equation. Phonological processing difficulties can make decoding harder, because the child's sound system — the foundation for sounding out words — is less reliable. And if speech difficulties are part of a broader language profile, language comprehension may also be affected.
What the Research Tells Us
Professor Gail Gillon's extensive research at the University of Canterbury has been particularly influential in this area. Her work has consistently shown that children with speech sound difficulties often have weaker phonological awareness skills — the ability to identify, blend, and manipulate sounds in words.
Gillon's research demonstrates that phonological awareness is one of the strongest predictors of early reading success, and that children with speech sound difficulties benefit significantly from phonological awareness intervention — ideally before they start formal reading instruction.
Importantly, her work also shows that integrating phonological awareness goals into speech therapy can improve both speech and early literacy outcomes at the same time. That's a real win, because it means therapy can do double duty.
Australian research supports these findings. Nathan and colleagues (2004) found that children with persisting speech sound difficulties at school entry had significantly weaker literacy outcomes than those whose difficulties had resolved. Studies consistently show that children who enter school with unresolved speech sound difficulties are more likely to experience challenges with reading accuracy, spelling, and reading comprehension in the early primary years.
How Speech Sound Difficulties Can Affect Learning
Let's make this practical. Here are some of the ways speech sound difficulties can show up in the classroom:
Phonics and Decoding
When children learn phonics at school, they're learning to connect letters with sounds. If a child's internal representation of those sounds is unclear — if they're not sure of the difference between "t" and "k," for example — then matching those sounds to letters becomes harder. They might confuse letters, struggle with sounding out unfamiliar words, or find blending sounds together difficult.
Spelling
Spelling requires children to break words into their individual sounds and then choose the right letters. If a child has difficulty identifying or sequencing sounds in spoken words, their spelling will often reflect those same patterns. You might see sound substitutions, missing sounds, or simplified words in their written work — mirroring the patterns you hear in their speech.
Reading Fluency
Children who have to work harder to decode individual words read more slowly and with less fluency. This extra effort can affect comprehension too, because so much of their mental energy is going into figuring out the words that there's less left over for understanding the meaning.
Many of the children I've supported with early reading difficulties had a speech sound history that no one had joined up to their literacy struggle — the link between how they sound out speech and how they sound out words on a page is often invisible to the adults around them.
Confidence and Engagement
This one is easy to overlook, but it matters. Children who find reading difficult often start to avoid it. They may become reluctant readers, resist reading aloud, or develop anxiety around literacy tasks. Over time, this avoidance creates a gap — children who read less get less practice, which makes the difficulty grow.
Why Early Intervention Makes Such a Difference
The research is consistent on this point: early intervention matters. Addressing speech sound difficulties before school — or in the early years of school — gives children the best chance of developing the phonological skills they need for reading.
Here's why timing is so important:
- Phonological awareness develops rapidly between ages 3 and 6 — this is the window where targeted support has the biggest impact
- Early reading instruction builds on phonological skills — children who start school with strong sound awareness are better positioned to benefit from phonics teaching
- Gaps widen over time — a small difficulty in Prep can become a significant challenge by Year 3 if it's not addressed
- Intervention works — Gillon's research and others have shown that phonological awareness intervention is effective, especially when it's started early and integrated with speech sound therapy
When school's involved, hearing matters even more. If speech sounds are affecting reading and spelling, hearing becomes even more important — children have to hear a sound clearly before they can match it to a letter. A paediatric audiologist can tell us quickly whether that's part of the picture.
What Can Parents Do?
If your child has speech sound difficulties — or if you're noticing early signs that reading and writing might be a challenge — a few things can help point you in the right direction:
- A speech pathology assessment is the most useful starting point. A thorough assessment looks at your child's speech sounds, phonological awareness, and early literacy skills together, which is where the most useful information usually lives. If your child is already in speech therapy, it's worth asking whether phonological awareness goals are part of the plan — the best outcomes tend to come from integrating them rather than treating them separately.
- Shared reading is the everyday piece most families can lean on. Reading together builds vocabulary, language comprehension, and familiarity with print. It doesn't need to be long — even 10 minutes a day matters, and playful sound games (rhyming, clapping syllables, noticing beginning sounds) can come along for the ride.
- Stay in touch with your child's teacher. Teachers are often the first to notice when a child is finding literacy tasks harder than expected, so an open line between home and classroom means concerns get picked up early.
The Bottom Line
Speech and literacy are deeply connected. Children who struggle with speech sounds — particularly phonological processing — are at greater risk of reading and spelling difficulties. But the good news is that early, targeted intervention can make a genuine difference. If you're concerned about how your child's speech might be affecting their learning, get in touch with our team — Speaking Speech Pathology offers mobile speech pathology in your home across Brisbane's south side and Logan. Any actual clinical work — assessment, diagnosis, or therapy — happens through a proper consultation tailored to your child.
Alexandra Bouwmeester is a Senior Speech Pathologist (MSPA, CPSP) and certified Sounds-Write Clinician with over 14 years' experience supporting children's literacy. She has a particular interest in the connection between speech sounds and reading.
References
- Queensland Department of Education. (n.d.). Reading and Writing Centre.
- Gillon, G. T. (2018). Phonological Awareness: From Research to Practice (2nd ed.). Guilford Press.
- Nathan, L., Stackhouse, J., Goulandris, N., & Snowling, M. J. (2004). The development of early literacy skills among children with speech difficulties. Journal of Speech, Language, and Hearing Research, 47(2), 377–391.
