A phonological disorder is a speech sound disorder: a child keeps swapping or dropping sounds in patterns across many words, such as "doe" for "go" or "lie" for "like", after the age most children have stopped. This makes their speech harder to understand than other children's the same age, and it differs from an articulation disorder, where a child has trouble forming a sound. A speech pathologist can tell which one your child has.
If people often ask you what your child just said, this page explains the kinds of speech sound difficulty, what is typical at each age, the signs to act on, and how to get help in Australia.
Phonological or articulation: what the difference is
"Speech sound disorder" is the umbrella term. The Australian Government's Medicare list of speech sound disorders names four kinds: articulation disorder, phonological disorder, childhood apraxia of speech and dysarthria.
| Type | What is going on | Example |
|---|---|---|
| Articulation disorder | Trouble forming a particular sound with the lips, tongue, teeth and palate | A lisp |
| Phonological disorder | The child can usually make the sounds, but uses them in patterns of swaps or gaps in words | "doe" for "go", "lie" for "like" |
| Inconsistent phonological disorder | The same word comes out differently each time the child says it | One word, several versions |
| Childhood apraxia of speech | Trouble planning the movements for speech | A speech pathologist assesses this separately |
According to the Royal Children's Hospital, a phonological disorder often affects many sounds rather than one, and can make a child much harder to follow than an articulation problem on its own. Some speech pathologists also separate a phonological delay, where a child makes the errors of a younger child, from a disorder, where the errors are unusual. A speech pathologist decides which description fits your child.
Sources: Medicare Benefits Schedule (speech sound disorders fact sheet); Royal Children's Hospital Melbourne (articulation and phonological disorders); Parliament of Australia submission by Dodd, Morgan and Reilly (speech sound disorder types); NSW Government, Western NSW speech pathology (children's speech); Better Health Channel (childhood apraxia of speech).
What is typical at each age
Young children simplify words while they learn to talk. The Western NSW Local Health District speech pathology service gives examples of the predictable patterns: "ghetti" for "spaghetti", "dun" for "sun", "bish" for "fish" and "wabbit" for "rabbit". The Victorian Government's early childhood guide calls the "wabbit" pattern gliding and lists it as typical between about 1 and 3 years.
How much of your child's speech other people understand is a useful guide. A summary of speech research by Charles Sturt University says 2-year-olds are understood at least half the time, more often by their parents, and 4- and 5-year-olds most of the time, even by strangers. The NSW service says that by the end of preschool, most people, even strangers, should understand a child. Compare with how strangers understand your child, not you: you know their speech best.
The NSW service gives these average ages for learning English consonants, taken from 15 studies:
| Average age | Sounds |
|---|---|
| 2 to 3 years | p, b, m, d, n, h, t, k, g, w, ng, f, y |
| 4 years | l, j, ch, s, v, sh, z |
| 5 years | r, zh, th (as in "this") |
| 6 years | th (as in "thin") |
These are averages, so many children learn some sounds later. Raising Children Network says most children learn several sounds later than that: l, r and v at around 6 years, and th and z at around 7 to 8 years. The two sources differ by two years or more for some sounds (for z, 4 years against 7 to 8 years), so use the table as a rough guide, not a deadline.
Sources: NSW Government, Western NSW speech pathology (children's speech); Victorian Government (speech sounds, early childhood literacy toolkit); Charles Sturt University (summary of speech acquisition); Raising Children Network (speech disorders).
Signs to see a speech pathologist
Raising Children Network suggests seeking help if your child:
- uses only a handful of different sounds at age 2
- says words differently from what you would expect for their age
- makes many speech errors and is hard for you to understand
- gets frustrated or upset when people do not understand them
- has hearing loss or has had a lot of ear infections
Children's Health Queensland lists speech that familiar people find hard to understand at 3 years, and speech that is hard to understand at 4 years, as red flags.
You do not need a set number of signs. The Royal Children's Hospital says a speech pathologist should assess your child if you, or someone who sees your child often such as their teacher, has any concern about their speech. If your child stops using speech or language skills they used to have, see your GP soon.
Sources: Raising Children Network (speech disorders; language at 2 to 3 years); Children's Health Queensland (red flags early identification guide); Royal Children's Hospital Melbourne (articulation and phonological disorders).
Get your child's hearing checked
Hearing loss can affect how a child's speech and language develop, says the Sydney Children's Hospitals Network. The Better Health Channel says to have your child's hearing tested if you have any doubt about it, and the same network lists unclear speech among the signs to see a doctor or audiologist. Speech pathologists will often ask whether your child has had a hearing check, and may suggest one.
For most children with a speech sound disorder there is no known cause. The NSW service says known reasons in some children include hearing loss, cleft palate, or a family member who has had speech difficulties.
Sources: Better Health Channel (hearing problems in children); Sydney Children's Hospitals Network (hearing loss in children); NSW Government, Western NSW speech pathology (children's speech; visiting a speech pathologist); Royal Children's Hospital Melbourne (articulation and phonological disorders); Raising Children Network (speech disorders).
How to see a speech pathologist in Australia
You can book a speech pathologist directly; the Better Health Channel says no doctor's referral is needed, although some funding needs one. Raising Children Network says that if you are worried, your GP or child and family health nurse can help you decide where to go.
Ways to pay:
- Public services. Community health and child development services can be free for eligible children, but may have waiting lists. For example, Perth's Child Development Service is free for eligible children in the metropolitan area, and says wait times vary with demand.
- Medicare. From 1 March 2026, speech sound disorders were added to the list of eligible conditions for a Medicare allied health scheme. The Australian Government says eligible patients can get rebates for up to 8 assessment and 20 treatment sessions, with a referral from a GP, specialist or consultant physician. Ask your GP whether it applies to your child.
- NDIS. The NDIS early childhood approach is for children under 9 with developmental delay or disability, and offers early supports for children under 6 with developmental concerns. The NDIS says it can help even if your child is not eligible for the scheme.
- Private health insurance may cover part of the cost.
When you call a service, ask how long the wait is and what you can do in the meantime. Write down the date you expect to be seen. If your child becomes more frustrated, harder to understand, or stops using sounds they had, call your GP before then.
Sources: Better Health Channel (speech pathologist service); Raising Children Network (speech pathologist); Child and Adolescent Health Service WA (Child Development Service eligibility); Medicare Benefits Schedule (speech sound disorders fact sheet); Australian Government Minister for Health (Medicare speech pathology sessions); NDIS (early childhood approach).
What assessment and therapy involve
At the first visit, a speech pathologist usually asks about your child's health and development, asks your child to say some words or point to pictures, and looks at their lips, teeth, tongue and the back of their mouth. Some assessments take more than one appointment. Raising Children Network says you might then get a report on your child's strengths and difficulties and a therapy plan.
Therapy sessions use games and activities, and speech pathologists suggest practice for home and school. Which approach they choose depends on the type of difficulty:
- For an articulation disorder, therapy usually works on one sound at a time.
- For a phonological disorder, one common approach uses pairs of words that differ by one sound, so the child hears that swapping the sound changes the word. Another, called cycles, works on one pattern for a set time before moving to the next.
- For an inconsistent phonological disorder, a speech pathologist may use a "core vocabulary" approach built on a set of everyday words.
A study of Australian speech pathologists from Flinders University found they often combine parts of several approaches. On the evidence, the same paper reports a review of six studies that found a small to moderate average effect of phonological therapy compared with no therapy, with a wide margin of uncertainty, and notes that most research has not used controlled designs. Researchers also stress matching the therapy to the type of speech disorder.
Sources: NSW Government, Western NSW speech pathology (visiting a speech pathologist); Raising Children Network (speech pathologist); Royal Children's Hospital Melbourne (articulation and phonological disorders); Flinders University, Furlong and colleagues (speech sound disorder therapy in Australian practice); Parliament of Australia submission by Dodd, Morgan and Reilly.
What you can do at home
- When your child says a word the wrong way, say it back the right way in your reply, as part of normal talk. If they say "I want my bot", you might answer "Your boat? Here's your boat." They do not have to say it after you.
- Avoid asking them to say a word again and again when it is hard for them. The NSW service says repeated attempts can frustrate children and make the right sound harder to learn.
- Praise your child when they try a word after you, and let it go when they do not.
- When you cannot understand them, ask them to show you or point, and give them time to say it slowly.
- Follow the home practice your speech pathologist gives you, so home matches the sessions.
Sources: NSW Government, Western NSW speech pathology (children's speech); Gold Coast Health (general strategies to support your child's speech development); Raising Children Network (speech disorders).
Reading, school and whether it lasts
Sources describe a link between speech sound difficulties and reading, not a certainty. The Royal Children's Hospital says phonological disorders have been linked to ongoing problems with language and literacy. A study in the Australian Journal of Teacher Education says children with speech sound disorders are more likely to have reading difficulties.
Some children grow out of a speech disorder and some do not. The Murdoch Children's Research Institute says some children grow out of it while others have long-term difficulties with communication, and the Royal Children's Hospital says most children with a diagnosed articulation or phonological disorder need speech therapy. Neither gives a way to tell in advance, so if you are unsure, ask for an assessment now.
For the order in which sounds usually develop, see how children learn speech sounds, and for when to book, the guide to when to see a speech pathologist. If your child is starting school, learning difficulties in children covers the reading signs to watch.
Sources: Royal Children's Hospital Melbourne (articulation and phonological disorders); Edith Cowan University, Australian Journal of Teacher Education (Daniel and McLeod 2017); Murdoch Children's Research Institute (speech and language disorders).
Your next step
If your child is often hard to understand, book a hearing check and a speech pathologist assessment, and ask your GP about the Medicare sessions. The speech delay hub brings together support for children who are slow to talk or hard to understand, and the speech therapy page explains what a speech pathologist does. When you are ready, find a children's speech pathologist near you.
