Speech Sound Development Milestones

The most useful measure: how much can a stranger understand?

Parents get very good at understanding their own child, which makes "can I understand them?" an unreliable test. Intelligibility to an unfamiliar listener is the measure that matters, and it has clear expectations:

• By 18 months — about 25 per cent of what a child says is understood by someone unfamiliar.
• By 2 years — about 50 per cent.
• By 3 years — about 75 per cent.
• By 4 years — close to 100 per cent, even if some sounds are still imperfect.

A four-year-old whom relatives regularly cannot understand should be assessed, regardless of what any milestone chart says about individual sounds.

Roughly when sounds arrive

There is real variation between children, and different studies place some sounds a little earlier or later. Treat this as a guide.

The later sounds — r, th, s and l — are the ones most often still developing at school entry, and are usually not a concern on their own before about six.

Normal patterns that should disappear

Young children simplify words in predictable ways. Each pattern has an age by which it should have stopped.

• Dropping the end of words ("cu" for cup) — gone by about 3.
• Repeating a syllable ("baba" for bottle) — gone by about 3.
• Simplifying clusters ("poon" for spoon) — gone by about 4.
• Front sounds for back ones ("tat" for cat, "do" for go) — gone by about 3½.
• Replacing l or r with w ("wed" for red, "yeyow" for yellow) — gone by about 5–6.
• "th" as f or d ("fumb" for thumb) — gone by about 5–7.

A pattern still present well past its age, or a pattern that is unusual rather than typical, is worth an assessment.

Refer earlier, not later, if…

• No babbling by 9 months, or babbling that stops.
• No first words by 15 months; fewer than 50 words by 2 years.
• No two-word combinations by 2 years.
• Speech is markedly less clear than other children of the same age.
• The child is frustrated, gives up, or has stopped trying to talk.
• Loss of speech or social skills the child previously had — always assess this promptly.
• Concerns about hearing, frequent ear infections, or glue ear. Have hearing checked first, always.
• Sounds are produced in an unusual way — a lisp with air escaping sideways, a very nasal voice, or difficulty coordinating longer words.
• Feeding difficulties alongside speech difficulties.
• A family history of speech, language or literacy difficulties.

What helps at home

• Model, do not correct. If a child says "tat", reply "yes, a cat!" — repeat it correctly and move on. Asking a child to say it again usually produces the same error and some embarrassment.
• Get face to face and slow down. Children learn sounds partly by watching mouths.
• Repeat the target sound often in ordinary conversation — many times, naturally, rather than as a drill.
• Give time to respond. Count to five in your head. Most adults wait about one second.
• Do not make them perform. "Say it properly for Grandma" teaches a child that talking is a test.
• Read together daily. Books expose children to sounds and words that everyday conversation does not.
• Reduce background noise during conversation — a television on is a significant barrier.

Two myths worth retiring

"Boys talk later." There is a very small average difference and it does not justify waiting. Delay costs more than an assessment does.

"Wait and see." Some children do catch up. The problem is that nobody can tell in advance which ones, and speech difficulties that persist into school are strongly associated with later reading and spelling difficulties. Early assessment costs an appointment; waiting can cost years.

Hearing first

Any concern about speech should be accompanied by a hearing check, even if hearing seems fine. Intermittent hearing loss from glue ear is extremely common in early childhood, fluctuates, and is easy to miss — and a child cannot reliably produce sounds they are not consistently hearing.