Toddler Lisp: Why It Happens, When to Worry, and How to Fix It

Your three-year-old says “thun” instead of “sun” and calls their favourite food “thpaghetti.” It’s adorable now, but you’ve started to wonder if they’ll grow out of it, or is it time to act? A lisp in toddlers is one of the most common speech patterns parents notice, and while some resolve naturally, others need professional support to ensure your child’s speech develops clearly.

The good news? Most lisps can be successfully treated with the right approach. Understanding what’s normal, what’s not, and how to get rid of a lisp begins with identifying the type your toddler has and determining when intervention is necessary.

Key Insights

• A lisp in toddlers is common. Some types are developmental and resolve by age 4.5–5, while others require speech therapy
• Interdental (frontal) lisps may disappear naturally; lateral and palatal lisps typically need professional help
• If your child is still lisping after age 4.5, book a speech pathology assessment
• Sydney families can access expert support to help their toddler develop clear, confident speech

What Is a Lisp in Toddlers?

A lisp happens when your toddler’s tongue sits in the wrong position while making “s” and “z” sounds. Instead of hearing “sun” or “zebra,” you might hear “thun” or “thebra.” Sometimes the sound comes out muffled, wet, or hissy rather than crisp and clear.

Lisps affect how certain sounds are produced, not whether your child understands language or knows what they’re trying to say. Most toddlers with lisps are perfectly understood in conversation, but the way specific sounds come out is noticeably different.

What Causes a Lisp in Toddlers?

There’s no single cause for lisps, which is why speech pathologists call them “functional speech disorders” — meaning there’s usually no structural problem with your child’s mouth or tongue. In most cases, toddlers develop a lisp because they’ve learned to position their tongue incorrectly when speaking, and that pattern becomes a habit.

Some contributing factors include:

• Tongue thrust patterns: If your toddler pushes their tongue forward when swallowing or speaking, this can create or reinforce a lisp. Prolonged dummy use or thumb sucking can strengthen these habits.
• Natural speech development: Younger toddlers are still mastering how to coordinate their lips, tongue, teeth, and breath to form clear sounds. The “s” sound typically develops around age 5, so some lisping before then can be part of normal development.
• Mouth breathing: Chronic allergies or sinus issues that keep your toddler breathing through their mouth may cause the tongue to rest flat and forward, affecting speech clarity.
• Learned patterns: Sometimes toddlers simply learn to say a sound incorrectly from the start, and without correction, that becomes their default way of speaking.

Types of Lisps

Not all lisps are the same. Speech pathologists identify four distinct types, and knowing which one your toddler has determines whether they’ll grow out of it or need support.

Interdental (frontal) Lisp

The tongue pushes between the front teeth, making “s” sound like “th.” This is the most common type in toddlers and often resolves naturally by age 4.5–5.

Lateral Lisp

Air escapes over the sides of the tongue instead of through the front, creating a wet or slushy sound. This type does not resolve on its own and requires speech therapy.

Dentalized Lisp

The tongue presses against the front teeth rather than behind them, creating a slightly muffled “s” sound. Like interdental lisps, this may resolve with maturity.

Palatal Lisp

The tongue touches the soft palate (roof of the mouth) instead of staying near the teeth, producing a windy, hissy sound. This type is rare but also requires professional treatment.

Do Toddlers Grow Out of Lisps?

“Do toddlers grow out of lisps?” is the question every parent asks. The answer depends entirely on which type of lisp your toddler has.

Interdental and dentalized lisps can be part of normal speech development. Many toddlers produce these patterns while they’re learning to coordinate their tongue movements. These types often disappear naturally by age 4.5–5 as your child’s speech matures.

Lateral and palatal lisps are not developmental. Children don’t spontaneously correct these on their own, and waiting won’t help. In fact, the longer these patterns continue, the more ingrained the habit becomes, making it harder to correct later.

By age 5, children should be producing the “s” and “z” sounds correctly. If your child is approaching school age and still lisping, that’s your signal to book an assessment with a speech pathologist.

How to Get Rid of a Lisp in Toddlers

If your toddler has an interdental or dentalized lisp and they’re under age 4, some home strategies can help support their speech development:

• Address breathing and oral habits. Treat any allergies or sinus problems so your toddler can breathe through their nose. Discourage thumb sucking and phase out dummy use, as these can reinforce forward tongue patterns.
• Model correct sounds naturally. When your toddler says “thun,” simply repeat it back correctly: “Yes, the sun is bright today!” 
• Read together. Point out “s” sounds in books and model them clearly. Make it playful, not corrective.

However, here’s the critical point: if your child is over 4.5 years old, has a lateral or palatal lisp, or you’re unsure which type they have, a professional assessment is the best next step. Home activities alone won’t fix lisps that require targeted speech therapy techniques.

When to See a Speech Pathologist

You should book an assessment if:

• Your toddler is 4.5–5 years old and still lisping
• You suspect a lateral lisp (wet, slushy sound)
• Your child is frustrated or self-conscious about how they sound
• Unfamiliar adults struggle to understand your child
• You’re unsure whether the lisp is developmental or needs treatment

A speech pathologist will conduct a thorough assessment to identify which type of lisp your toddler has, check their oral-motor skills, and determine whether therapy is recommended.Research on speech sound disorders shows that early intervention leads to better outcomes. The earlier you start, the faster your child will progress.

Get Expert Help for Your Toddler’s Lisp

Wondering whether your toddler’s lisp will resolve on its own or needs professional support? Eastside Speech Solutions offers comprehensive speech pathology assessments for Sydney families, helping parents understand exactly what type of lisp their child has, how to fix a lisp and what steps to take next.

Our experienced speech pathologists create tailored treatment plans that work with your family’s schedule and your child’s learning style. We’ll show you how to support your toddler’s speech development at home and provide expert guidance every step of the way. Most importantly, we help your child build the confidence to communicate clearly — now and as they grow.