What Is a Frontal Lisp? How to Support /s/ and /z/ Sounds at Home

Have you noticed that your child says “thun” instead of “sun” or “thoo” instead of “zoo”? Your child may have a frontal lisp, a speech sound difficulty that affects how /s/ and /z/ are produced.

Learning to produce speech sounds takes time, and some children benefit from extra support as their speech develops. In this article, we’ll explain what a frontal lisp is and share two activities you can try at home to support your child’s /s/ and /z/ sounds.

If you have concerns about your child’s speech development, a speech-language pathologist (SLP) can assess their speech and recommend strategies tailored to their needs.

What Is a Frontal Lisp?

A frontal lisp occurs when the tongue moves too far forward during the production of /s/ and /z/, sometimes protruding between the front teeth. This changes the direction of airflow and can make the sounds resemble “th.”

For example, a child might say:

• “Thun” instead of “sun.”

• “Thip” instead of “sip.”

• “Thoo” instead of “zoo.”

The /s/ and /z/ sounds require precise coordination of the tongue, jaw, and airflow. When the tongue moves too far forward, it can be more difficult to produce these sounds clearly.

A frontal lisp is one type of speech sound difficulty. A speech-language pathologist can help determine whether your child would benefit from speech therapy and which strategies are most appropriate.

How Can You Help Your Child Practice /s/ and /z/ at Home?

Speech-language pathologist Pam Marshalla discussed the role of tongue and jaw stability when helping children develop speech sounds (Marshalla, 2010). Rather than repeatedly reminding your child to “keep your tongue in,” you can try activities that help them explore how their mouth moves when producing sounds.

The following techniques are examples of ways to practise sound production. Not every strategy works for every child, so follow your SLP’s recommendations if your child is receiving speech therapy.

1. Try the “Eeee” Trick

The long “ee” sound can help some children explore a more stable tongue position. It may also provide a useful starting point for practising /s/. However, the tongue position for /s/ is different from the position used for “ee,” so your child may need help transitioning between the two sounds.

Step 1: Start with a smile

Ask your child to smile gently and say “eeee.” A mirror can help them observe their mouth movements.

Step 2: Practise the “eeee” sound

Encourage your child to hold the sound for a few seconds while keeping their tongue inside their mouth.

Step 3: Move towards /s/

If your child can produce the “ee” sound comfortably, try gently transitioning from “ee” into a long /s/ sound: “eeee-ssss.”

Step 4: Practise the target sound

Once your child can produce /s/ more clearly, practise it on its own before moving on to simple syllables or words, as appropriate.

Keep the activity short and playful. The goal is to help your child explore the sound rather than achieve perfect pronunciation right away.

2. Try the “Long T” Trick

Another technique sometimes used to help shape /s/ is to begin with the /t/ sound. The tongue placement for /t/ can provide a starting point for exploring the airflow needed for /s/.

Step 1: Start with /t/

Ask your child to say “t, t, t” slowly. Encourage them to notice where their tongue touches the area just behind their upper front teeth.

Step 2: Try adding a stream of air

If your child can do so comfortably, try stretching the release of the /t/ into a long /s/ sound: “tssssss.”

Step 3: Gradually shorten the transition

If your child can produce the sound successfully, try reducing the initial /t/:

“tssssss” → “tsss” → “ssss”

Step 4: Practise only if the sound is coming along comfortably

If your child continues to produce “th” or becomes frustrated, return to an easier step or pause the activity. A speech-language pathologist can help identify the tongue placement and cues that work best for your child.

Tips for Practicing Speech Sounds at Home

When supporting your child’s speech development, how you practice can be just as important as what you practice.

Here are a few ways to make home practice more positive:

• Keep practice short. A few minutes of enjoyable practice is often more manageable than a long session.

• Model the sound naturally. If your child says “thun,” you can respond warmly, “Yes, the sun is shining!” and model the word without asking them to repeat it repeatedly.

• Use a mirror if helpful. Some children benefit from seeing their mouth movements, while others find visual feedback distracting.

• Celebrate effort. Encourage your child when they try a new sound, even if it is not yet accurate.

• Avoid constant corrections. Frequent reminders can make speaking feel stressful. Keep communication enjoyable and focus on practice when your child is ready.

It is also important to remember that producing /s/ in isolation is different from using it accurately in words, sentences, and everyday conversation. Children may need support as they progress through these stages.

When Should You Seek Speech Therapy for a Frontal Lisp?

If your child consistently produces /s/ or /z/ like “th,” you may wish to consult a speech-language pathologist. An SLP can assess your child’s speech sound production, consider their overall speech development, and determine whether intervention is appropriate.

Speech therapy for a frontal lisp may include learning the correct tongue placement, practising airflow, producing sounds in increasingly complex contexts, and developing accurate speech during everyday communication.

The best approach depends on your child’s age, speech sound patterns, and ability to produce the target sounds. Home activities can be helpful, but they are not a substitute for an individualized assessment when one is needed.

Speech Therapy in Vaughan, Ontario

At Kurliand Speech Clinic, we provide speech therapy services for children and families in Vaughan, Ontario, and surrounding communities. Our services include in-clinic and in-home speech therapy in Vaughan, as well as virtual services across Ontario.

If you have concerns about your child’s speech clarity or difficulty producing sounds such as /s/ and /z/, we can help you explore the next steps.

Contact Kurliand Speech Clinic to learn more about our speech-language pathology assessments and therapy services.

Every child develops speech skills at their own pace. If you are concerned about your child’s speech, a speech-language pathologist can help you determine whether additional support may be beneficial.