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Is a lisp normal in a 5-year-old?

It depends entirely on which kind of lisp it is, and this is the thing most parents are never told. An interdental lisp — the tongue slipping between the teeth so “sun” becomes “thun” — is common at 5 and usually resolves; the norm for a clean S is around age 5, so a child sitting right at that line is not unusual. A lateral lisp — a wet, slushy S with air escaping over the sides of the tongue — is not a developmental stage. It does not resolve with age and it needs a speech-language pathologist. If your child’s S sounds slushy rather than “th”-like, that is the one to act on.

5 min read · Updated 9 August 2026

How to tell the two apart at home

You do not need any equipment. Ask your child to say a long “sssss”, and listen and look.

  • Interdental: you can usually see the tongue tip poking out between the front teeth. The sound is clean but wrong — it comes out as “th”. “Sun” becomes “thun”, “bus” becomes “buth”.
  • Lateral: the sound is wet, slushy, a little like a quiet SH mixed in. The tongue stays inside the mouth. If you hold a hand near the corner of their mouth you may feel the air escaping sideways rather than forward.

A third possibility, worth ruling out: some children simply drop S in some positions rather than distorting it. That is a different pattern again and belongs with a clinician if it persists past 5.

Why the distinction matters so much

An interdental lisp is a placement error that many children correct by themselves as their mouth grows and their motor control improves. Losing front teeth around 5 or 6 makes it temporarily worse in a way that means nothing.

A lateral lisp is a different kind of error: the airflow is going the wrong way, not just the tongue sitting in the wrong spot. Children do not grow out of it, and practising it at home without knowing what to correct tends to reinforce the pattern, because the child repeats the wrong airflow accurately hundreds of times.

That is the practical consequence. For one, waiting is reasonable. For the other, waiting costs time and home practice can actively make it harder to change later.

What is normal at 5, specifically

S is usually placed at around age 5 in English, alongside L, SH, CH, J and Z. R comes later, at around 6, and TH later still at around 7.

So a 5-year-old with a “th” lisp is at the edge of the norm rather than outside it. A 5-year-old with a “th” lisp who is also hard for strangers to understand, or who has several other sounds off as well, is a different picture and worth an assessment.

Missing front teeth are worth mentioning to anyone who assesses your child, but they are rarely the cause of a persistent lisp. Children with full sets of teeth lisp, and children with gaps do not.

If it is the interdental kind, what helps

  • Start at the end of words, not the beginning. Words ending in -ts — “boats”, “cats”, “lights” — often produce a correct S almost by accident, because the T puts the tongue in nearly the right place. That is a much easier entry point than “sun”.
  • Teeth gently together. Most of the correction is simply keeping the tongue behind the teeth rather than between them, and closed teeth make that hard to get wrong.
  • Use a mirror. Unlike R, this is an error a child can see themselves making, which makes it one of the more satisfying sounds to work on.
  • Keep it to about ten minutes a day. Short and daily beats long and occasional, and it keeps practice from becoming something they dread.

When to book an assessment

Arrange one if the S sounds slushy rather than “th”-like, if your child is 6 or older and the lisp has not shifted, if several sounds are affected rather than just S, if strangers struggle to understand them, or if you have any concern about their hearing.

Our free sound check asks specifically about the slushy version, and if you tell it that is what you are hearing, it will send you to a professional instead of giving you a practice plan.

Common questions

Will my child grow out of a lisp?

An interdental lisp — the “th” kind — often resolves on its own, and it is common up to around age 5. A lateral lisp, the wet or slushy kind, does not resolve on its own at any age and needs a speech-language pathologist. Because the two look similar to a parent but behave completely differently, identifying which one you are hearing is the most useful thing you can do.

Do missing front teeth cause a lisp?

They can make an existing one temporarily more noticeable around age 5 to 7, but they rarely cause a persistent lisp. Children with complete teeth lisp and children with gaps often do not, so missing teeth are not a reason to postpone getting a persistent lisp looked at.

At what age should a child say S clearly?

Around age 5 for English-speaking children. A 4-year-old with an unstable S is well within the normal range; a 6-year-old with a persistent one is worth having assessed, regardless of which kind of lisp it is.

This guide is general information about typical speech development. It does not diagnose and it is not a substitute for assessment by a licensed speech-language pathologist.