Someone at the playground says "he'll talk when he's ready" and someone at nursery says "you should get that looked at", and you go home with the same question you arrived with. Speech is one of the few areas of early development where the normal range is genuinely enormous, which makes it very hard to tell a slow starter from a real delay.
Here is what the milestone data actually says, why the official American checklist changed in 2022 and upset a lot of speech therapists, what happens to late talkers over the following fifteen years, and the small number of signs that are worth acting on quickly rather than waiting out.
What counts as a speech delay?
A speech delay means a child is developing speech and language along the usual path but noticeably later than most children their age. It is different from a speech disorder, where the pattern itself is unusual rather than just late.
Two distinctions save a lot of worry. Speech is the physical production of sounds. Language is understanding and using words to communicate. A child can have clear speech and weak language, or the reverse. And understanding almost always runs ahead of talking, so a 2-year-old with fifteen spoken words who follows two-step instructions is in a very different position from one who does neither.
What should a child be saying at 2, 3, 4 and 5?
Use ranges, not single numbers. The figures below combine the American Speech-Language-Hearing Association milestone chart with the NIDCD summary of typical development.
| Age | Typically expected | Worth a conversation if |
|---|---|---|
| 24 months | 50 or more words, starting to join two together | Fewer than 25 words, or no two-word combinations |
| 3 years | Short sentences, asks simple questions, familiar adults understand most of it | Mostly single words, or you rarely understand your own child |
| 4 years | Four to five word sentences, tells a simple story, answers who and where | Strangers often cannot follow, or grammar is very reduced |
| 5 years | Full sentences, retells events in order, speech mostly clear | Persistent sound errors, or trouble following classroom instructions |
We broke the vocabulary side of this down further in how many words a 4-year-old should know.
How much of my child's speech should a stranger understand?
This is the most useful single test, and most parents have never heard of it. Because you understand your own child, your ear is the worst possible instrument. What a stranger catches is the honest measure.
Hustad and colleagues recorded 538 typically developing children and had 1,076 adults transcribe what they heard, published in the Journal of Speech, Language, and Hearing Research. For the average child, sentences reach 50 percent intelligibility at about 2 years 10 months, 75 percent at about 3 years 10 months, and 90 percent at about 5 years 2 months.
Note how late full clarity arrives. A 3-year-old whose speech a stranger understands only half the time is not unusual. The variation is also enormous: at 30 months, single-word intelligibility ranged from 18 percent at the 5th percentile to 74 percent at the 95th.
Why did the CDC change its milestones in 2022?
Because it changed what the milestones were for. In February 2022 the US Centers for Disease Control and Prevention updated its checklists, adding 15-month and 30-month lists, and shifted from listing what the average child does to listing what most children (roughly 75 percent) do. The reasoning was set out in a 2022 paper in Pediatrics by Zubler and colleagues.
In practice that moved "says 50 words" from 24 months to 30 months, and a lot of speech-language pathologists objected loudly. Their argument is that a checklist designed to avoid over-referral will inevitably delay referral for the children who need it most, and that ASHA's own guidance still points to around 50 words by 24 months.
Both positions are defensible, and the practical takeaway is the same either way. The checklist is a screening tool, not a verdict. If your instinct says something is off at 24 months, you do not have to wait until 30.
Do late talkers catch up?
Most do, but "most" is not "all", and catching up is not the same as no trace left. Roughly half of children whose language is significantly delayed at 24 to 30 months have caught up by age 4 or 5, and the majority score in the normal range on vocabulary by 3 and on grammar by school age.
Somewhere between 20 and 40 percent, however, continue to show difficulties past age 3 and are later identified with a language disorder, according to reviews of late language emergence. And Leslie Rescorla's follow-up of late talkers to age 17 found that although they performed in the average range, they still scored significantly lower than matched peers on vocabulary, grammar and verbal memory.
Rescorla's own review of the question, "Late talkers: do good predictors of outcome exist?", is refreshingly honest that we cannot reliably pick out in advance which toddler is which. That is exactly why "wait and see" is a gamble rather than a plan.
Which red flags are not about word counts?
Some signs matter more than vocabulary size, at any age.
Signs worth raising promptly with a professional
- Loss of words or skills your child previously had, at any age
- Little or no gesturing: no pointing, waving or showing you things by 15 to 18 months
- Not responding to their name, or seeming not to hear you consistently
- Difficulty understanding simple instructions, not just difficulty speaking
- Little interest in communicating at all, rather than trying and failing
- Frequent frustration or meltdowns tied specifically to not being understood
A hearing test is the first step in almost every case, including for children whose hearing seems fine. Intermittent hearing loss from repeated ear infections is common and easy to miss.
What actually helps at home?
Back-and-forth, more than input volume. This is one of the better-evidenced findings in the field: Rachel Romeo and colleagues recorded the home language of 4 to 6-year-olds and scanned their brains, and found that the number of conversational turns predicted activation in Broca's area and verbal skill, independently of how many words the children heard and of family income. The study is in Psychological Science.
So the useful moves are unglamorous. Pause after you speak and count to five. Ask questions that cannot be answered with yes. Repeat what your child said and add one word to it. Narrate what you are doing. Read the same book again and let them fill in the line.
Anything that produces more turns helps, which is part of why children who talk to themselves during play are doing something useful rather than odd, as we wrote in why children talk to themselves. A talking companion such as Ted can add turns to a day that would otherwise have few, because it waits, responds and asks back in the child's own language. To be clear, it is not a therapy tool and it does not assess anything. If you suspect a delay, the person you need is a speech-language pathologist, not a toy.
When should I call someone?
When you have wondered twice. There is no waiting list for worrying, and an evaluation costs you an afternoon.
Concretely: no words by 15 months, fewer than 25 words at 2 years, no two-word phrases by 2 and a half, speech that strangers cannot follow at all by 3, or any loss of skills at any age. Start with your paediatrician or GP, ask for a hearing check, and ask to be referred for a speech and language assessment. Early intervention services in many countries accept parent referrals directly.
Frequently asked questions
How do I know if my child has a speech delay?
Compare against age ranges rather than other children you know: around 50 words and two-word combinations by 2, short sentences by 3, and speech that unfamiliar adults can mostly follow by 4. Persistent shortfalls in those areas, or any loss of skills, are reasons to ask for an assessment.
Is it normal for a 3-year-old to be hard to understand?
Yes, to a degree. For the average child, sentences are only about 50 percent intelligible to an unfamiliar listener at 2 years 10 months, and 75 percent at nearly 4. Being partly unclear at 3 is expected; being completely unintelligible is not.
Do most late talkers catch up on their own?
About half of children delayed at 24 to 30 months catch up by 4 or 5, and most score in the normal range by school age. But 20 to 40 percent continue to have difficulties, and there is no reliable way to tell in advance which group a toddler belongs to.
Does being bilingual cause speech delay?
No. Bilingual children hit the major milestones on the same timeline as monolingual children. Their vocabulary in each individual language may be smaller for a period, but their combined vocabulary across both languages is comparable.
What is the first thing to do if I am worried?
Book a hearing test and speak to your paediatrician or GP. Hearing problems, including intermittent loss from ear infections, are one of the most common and most treatable causes of delayed speech.