Is a Lisp Normal at 3? Toddler Lisps at 2 and 3, Explained

The short answer: a “th” S is common at 3

Often, yes. If your 2- or 3-year-old says “thock” for sock or “thun” for sun, that is an interdental (frontal) lisp. An NHS children’s therapy service describes this pattern as common in children up to about age 5 and part of typical speech development.³

S and Z are late sounds. A 2020 review of US English consonant development pooled 15 studies and 18,907 children. It found /s/ and /z/ were acquired by 4;0–4;11 (years;months) at the 90% criterion, while early sounds such as /p/, /b/, /m/, /n/ and /d/ were acquired by 2;0–2;11. At 2 and 3, many children are still working on S and Z.¹

The exception is a wet or slushy S, where air escapes over the sides of the tongue. That can be a sign of a lateral lisp. The same NHS source says a lateral lisp is not part of typical development, and that a child with one may benefit from a speech and language therapist’s support.^3,4

What S and Z usually sound like at 2 and 3

At 2: often missing or swapped

At 2, S and Z are often still missing, swapped or inconsistent. RCSLT guidance says that before about 3, children often leave off the last sound of a word (“bus” can sound like “bu”), and that from 2 to 3 they are starting to use S, but not consistently, so “sun” might come out as “tun.” In the US review, studies using a 50% criterion put /s/ and /z/ at 2;0–2;11, but the stricter 90% mark isn’t reached until 4;0–4;11.^1,5

At this age, overall understandability tells you more than any single sound. NHS guidance on unclear speech says close family should usually be able to understand a child by about 2½.¹¹

At 2½ to 3: S appears, but stopping is common

Around 2½–3, children often find long sounds like S and F hard and swap in a short sound, such as “dun” for sun or “bish” for fish. This is called stopping. It is a typical simplification rather than a lisp. A lisp is when a child is clearly trying to say S but it comes out sounding different.^11,12,4

One NHS training resource says stopping on S, V and Z usually fades at about 3;6. Treat that as a guideline, not a firm rule.¹²

At 3: a “th” S is common

By 3, many children attempt S but let the tongue come between the front teeth, so S comes out sounding like “th” (“thock” for sock). NHS parent guidance describes this interdental pattern as common and part of typical development. For when it usually fades, see our page on when a lisp goes away, which covers that question in full.³

What “90% by 4;0–4;11” actually means

An age-of-acquisition figure always depends on a criterion. “Acquired by 4;0–4;11 at the 90% criterion” means that, in the studies reviewed, 90% of children in that age band produced the sound correctly, mostly in single words. It does not mean a 3-year-old without a clear S is behind. In the same review, studies using a 75% criterion put /s/ and /z/ at 3;0–3;11, so some children are still learning these sounds at 3 and even 4.¹

The norms also vary. The studies used different tests, criteria and groups of children, and one 1931 study reported that, at the 90% criterion, /s/ and /z/ were not achieved even by 6;11. Most English consonants are acquired by 5;0, which matches a review of 27 languages. These are US figures, so read them as a range, not a cut-off.^1,2

Which lisp patterns are common at this age, and which aren’t

Speech and Language UK describes how a lisp can sound: “slushy,” “wet,” “hissy” or like “th,” while the child is clearly trying to say S. At 2 and 3, which of these you hear matters more than whether there is a lisp at all.⁴

The evidence on palatal and whistling S is thin. We couldn’t find a published source on how common these are in toddlers, so we won’t give you a number. What parent guidance does say is that an unusual type of lisp is a reason to get help.⁴

You may see percentages quoted for each pattern. One Australian community study looked at 143 children aged 4 to 5 whose parents or teachers had raised concerns. Of these children, 39.9% had interdental lisps on /s/ and /z/, 17.5% dentalized other sibilants, and 13.3% had lateral lisps. Because these children’s speech had already raised concern, the figures show that lateral lisps do appear in preschoolers, but not how common each pattern is in all young children, and they don’t cover 2- and 3-year-olds.¹³

Dummies, bottles, thumb-sucking and open mouths: what the evidence says

There is no strong evidence that a dummy (pacifier) causes a lisp, and the research on dummies and speech in general is small and mixed. Speech and Language UK says no cause of lisps is known. It also says jaw, teeth and tongue position and long-term dummy or bottle use have been linked to lisps traditionally, without strong evidence.^4,6,9

Dummies

A UK study of dummy use and speech included 100 children aged 2 to 5. Most speech outcomes were not linked to dummy use. More frequent daytime use was linked to more atypical (unusual) speech errors, but that link was not seen in children older than 38 months, the sample’s median age. The authors call the evidence base “very small” and say these errors may resolve over time. The study did not measure lisps specifically.⁶

A 2025 study of 98 children aged 18 to 36 months found no link between pacifier use and vocabulary, and described the wider evidence on speech and language as inconsistent.⁹

The Royal College of Speech and Language Therapists (RCSLT), the UK professional body, says using a dummy to soothe a child does not affect speech development. It advises against long periods of daytime use when a child is starting to talk, and recommends taking the dummy out when the child talks.⁵

Advice does differ. An Australian charity says prolonged dummy use has consistently been shown to raise the risk of speech sound disorder, and one NHS trust advises stopping by the first birthday. This page follows the RCSLT and the UK study and doesn’t set a deadline. Decisions about stopping a dummy for teeth or sleep belong with your doctor, health visitor or dentist.^15,10,5,6

Bottles and thumb-sucking

A study of 128 children aged 3–5 in Chile found about three times the odds of a speech disorder in children who sucked their fingers, or who used a pacifier for 3 years or more. Starting a bottle only after 9 months was linked to lower odds. The study is easy to over-read. It is a single study, the habits were reported by parents, speech was measured at one point in time, and it did not look at lisps specifically. It shows a link, not a cause.^7,8

Open mouth or forward tongue

ASHA lists two possible signs of an orofacial myofunctional disorder that are relevant here: a forward or interdental tongue-resting posture, and distorted S and Z (often an interdental lisp). It lists drooling as a sign specifically after age 4. At 2–3, an open-mouth posture is something to mention to an SLP, doctor or dentist rather than assess at home. We don’t suggest blowing or tongue exercises as a lisp fix.¹⁴

Simple play that models S, without drilling

At this age the job is modelling, not correcting. Speech and Language UK suggests focusing on what your child says rather than how they say it, being positive, and saying the word back clearly without worrying if your child can’t copy it yet. NHS guidance also suggests modelling the word and not putting pressure on your child to copy you.^3,4

• Model, don’t correct. If your child says “thock,” answer naturally: “Your blue sock? Here’s your sock!”
• Pick 4 or 5 everyday S words, such as sock, soap, sandwich or “sit down,” and use them often. Stretch the S a little (“sssock”), and let your child join in only if they want to.
• With a 3-year-old, play a simple I Spy for S things versus “th” things.
• Fill a feely bag with toys that start with two different sounds, such as S and D. For a 2-year-old, skip the guessing and just name what comes out.
• Hiss like a snake, or like a tire letting its air out, during pretend play. It’s a long, fun S with no test attached.
• Try mirror play only if your child enjoys it: show how your tongue stays behind your teeth when you say S.
• If your child uses a dummy, keep it for soothing or sleep and out of the way during daytime play and talking.

Where these ideas come from: I Spy, mirror play and everyday words are from NHS parent guidance, and the feely bag is from an NHS training resource. The snake play and the 2-year-old version of the feely bag are our own suggestions, not from a published source.^3,12

Speech and Language UK also notes that some families accept a lisp as part of who their child is. Whatever your view, play should stay play.⁴

When to ask for an assessment

Guidance on when to refer differs between sources. One NHS trust suggests support for a lateral lisp without stating an age. Another suggests referral for unusual articulation, such as a lisp, from age 5. Speech and Language UK suggests getting help if a child is hard to understand or the lisp is an unusual type. The honest summary: the RCSLT says a referral can be considered at any age, so a speech-language pathologist can advise if you’re worried, and a slushy or unusual S is a reason to ask sooner.^3,11,4,5

• The S sounds wet or slushy, or otherwise unusual, such as “sh”-like or whistly.
• Close family find your child hard to understand by about 2½, or your child isn’t using speech sounds by 2.
• Your child seems frustrated or upset about talking.
• You have concerns about hearing, mouth breathing, a constant open-mouth posture or drooling.
• You are simply worried. You don’t need to wait for a set age to ask.

How your child feels about talking matters. In the Australian preschool study, children who saw an SLP were more likely to show distress about their speech and to be hard for strangers to understand. Hearing is part of the picture too: the RCSLT includes it in its speech sound disorder guidance.^13,5

• When does a lisp go away? The age data
• Speech milestones at 3 years
• Lateral lisp: the wet, slushy S
• Lisp in children: the types at a glance

Where SpeechStep fits, and where it doesn’t

SpeechStep is speech-practice software for ages 4 and up. It isn’t designed for 2- and 3-year-olds, it isn’t therapy, and it doesn’t diagnose. Its automatic listening for S and Z is a preliminary screen that never names a lisp type. For a toddler, the play ideas above, plus an SLP for any concern, are the right tools.

Frequently asked questions

References

15 sources from authoritative bodies. Last reviewed October 2026.

1. 1.Peer-reviewedCrowe & McLeod — Children’s English Consonant Acquisition in the United States: A Review — Peer-reviewed review, 2020.
2. 2.Charles Sturt University, Multilingual Children’s Speech (S. McLeod)Learning English consonants — Researcher-hosted resource page, 2024.
3. 3.GovernmentLisps — NHS parent information (Whittington Health, Islington children’s therapies; last updated 2025), 2025.
4. 4.Speech and Language UK (charity)Lisps (families) — Charity parent information (undated; accessed 2026), 2026.
5. 5.Royal College of Speech and Language TherapistsSpeech sound disorders – overview — Professional-body clinical guidance (last updated 2024), 2024.
6. 6.Peer-reviewedStrutt, Khattab & Willoughby — Does the duration and frequency of dummy (pacifier) use affect the development of speech? — Peer-reviewed study (n = 100, UK), 2021.
7. 7.Peer-reviewedBarbosa et al. — The relationship of bottle feeding and other sucking behaviors with speech disorder in Patagonian preschoolers — Peer-reviewed observational study (n = 128, Chile), 2009.
8. 8.University of WashingtonInfant sucking habits may affect how baby talks — University news release, 2009.
9. 9.Peer-reviewedBarca, Mazzuca & Borghi — Impact of pacifier use and parenting characteristics on toddlers’ vocabulary development — Peer-reviewed study, 2025.
10. 10.GovernmentChildren’s Speech and Language common queries — NHS parent information (Wirral Community Health and Care; last reviewed 2024), 2024.
11. 11.GovernmentUnclear speech — NHS parent information (Lancashire and South Cumbria; undated, accessed 2026), 2026.
12. 12.GovernmentSupporting School Age Children with Speech Sound Difficulties — NHS training resource (Children & Family Health Devon), 2021.
13. 13.Peer-reviewedMcLeod, Harrison, McAllister & McCormack — Speech Sound Disorders in a Community Study of Preschool Children — Peer-reviewed study (Australian concern-identified sample of 4- to 5-year-olds, n = 143), 2013.
14. 14.ASHAOrofacial Myofunctional Disorders — Practice Portal page (undated; accessed 2026), 2026.
15. 15.Hear and Say (Australian charity)Dummy Use and Speech Development — Charity article (undated; accessed 2026), 2026.