Lisps – when ‘s’ is hard to say


When I tell people that I am a Speech Pathologist, more often than not I hear something along the lines of “oh yeh, so you work with lisps and things?” While this is only one of many different areas that Speech Pathology can assist with, I do in fact receive a large number of referrals for children who struggle to say their ‘s’ sound. In this post, I hope to give readers an understanding of how to identify a lisp, when to seek help, and what to expect from your therapy sessions.

What impact does a lisp have?

An isolated difficulty clearly pronouncing the ‘s’ sound (with no other speech errors present) does not tend to impact on a person’s overall ability to be understood, also known as their ‘intelligibility’. However, the ‘s’ sound occurs frequently in many English words. The number of words that start with an ‘s’, have an ‘s’ in the middle or an ‘s’ at the end is quite high. For example, every time we use a plural word form (to show that there is more than one) we add an ‘s’ at the end of a word. As a result, when a child mispronounces this sound consistently in their speech, the impact it has on the overall way that their speech sounds can be quite noticeable.

What is a lisp?

It is important to first understand the difference between a lisp and a phonological speech error. Phonological disorder describes difficulties using (not making) speech sounds. In this case, children may be able to say an ‘s’ sound clearly, but they may always use a ‘t’ sound as a replacement (e.g. saying ‘tun’ for ‘sun’). The child may fail to develop the understanding that sounds hold meaning, and that when they use the wrong sound, people might not understand them. In therapy, we use contrasting words pairs to teach the child about when and why to use speech sounds. These types of speech errors are related to linguistic (language) disorders, and are more likely to improve over time as a child’s awareness and self-monitoring skills improve.

Lisps, however, are speech disorders. They are a result of difficulties with motor function – moving the muscles of the mouth correctly in order to shape the ‘s’ speech sound clearly. During development, the child has learned to say the ‘s’ sound incorrectly and this articulation error has become a habit. Over time, if a child never learns how to say the sound correctly the ‘habit’ may become more ingrained and harder to break as a result. Speech therapy will therefore teach the child how to say a correct ‘s’ sound, then implement plenty of guided practice to help the child feel comfortable and automatic with their new motor skill.

What are the different types of lisps?

An image of a therapist teaching a child to pronounce the letter S at Learn and Grow TherapyWhen we say a clear ‘s’ sound, our tongue must create a very specific shape. The sides of the tongue press up against the top teeth, and the middle of the tongue creates a ‘central groove’ in which the air flow travel down. When air travels through this small space, a high frequency, whistling ‘s’ sound is created. A lisp results from difficulties shaping the tongue in this precise way. There are three types of lisps:

  1. Interdental Lisp – produced when the tongue protrudes out between the teeth, creating a sound similar to a ‘th’ sound. An interdental lisp is considered ‘typical’ (seen in normal development) until the age of 4½ years. After this time, the error is classified as ‘delayed’ and therapy may be required.
  1. Lateral Lisp – produced when the tongue bunches together in the middle of the mouth (similar to the tongue’s position during the ‘l’ speech sound). Air flows along the sides of the tongue (laterally) creating a ‘slushy’ sounding ‘s’ – think of Sid from Ice Age! Lateral lisps are ‘atypical’ (not part of normal development) and Speech Therapy is recommended for anyone with a lateral lisp.
  1. Palatal Lisp – produced when the middle of the tongue comes in contact with the back of the throat (soft palate). Palatal lisps are also considered ‘atypical’ in development and therapy is recommended.

When is Speech Therapy recommended?

Lisps tend to be one of the errors in speech production that are more likely to stick around into adolescence and adulthood. However, some lisps may be more likely to resolve naturally than others. The general consensus among most Speech Pathologists is that the likelihood of a child ‘growing out of’ an interdental lisp is greater than that of a lateral or palatal lisp. As a result, most Speech Pathologists will recommend waiting until a child is 4 ½ years old before starting therapy to target an interdental lisp. However, interdental lisps for some children can be as persistent and difficult to treat as palatal or lateral lisps. The longer the child spends using the mispronounced ‘s’, the stronger the ‘habit’ becomes and the longer it might take to teach the child how to use a clear ‘s’ easily and naturally in their everyday speech. Waiting well past 4 ½ years is therefore not recommended. For any person who has a lateral or palatal lisp, speech therapy is usually indicated.

How does Speech Therapy work?

The first step of therapy is to help the child to shape a clear, crisp, high frequency ‘s’ sound (by itself). Speech Pathologists will use a number of techniques to support a child through this often challenging process. ‘Visual supports’ may include the use of mirrors, mouth puppets, pictures or diagrams of the mouth, and modelling of the ‘s’ sound. ‘Verbal prompts’ will involve talking about how to move parts of the mouth to make the sound, as well as feedback about the quality of the ‘s’ sound e.g. “that ‘s’ was a bit slushy”.  Speech Pathologists trained in PROMPT Therapy can also use tactile and kinaesthetic prompting. This involves placing the fingers on specific points of the face to show muscles how to move correctly. Speech therapy can be a bit of trial and error to find out which types of prompting is most helpful for each individual child.

Achieving a clear ‘s’ sound by itself is only the first step. Learning to use the sound naturally and automatically in everyday speech requires exposure to frequent and repetitive practice. The more a child practices the sound correctly, the stronger the new motor pathway in the brain becomes and the easier it will become for the person to use the sound without thinking about it. Think about learning how to write with your left hand (if you are right hand dominant). Initially, you will feel most comfortable with your right hand so you will naturally want to keep switching back. Writing with your left hand will be slower, will take more concentration and will feel awkward. However, with consistent practice you will begin to feel more confident and comfortable, and your writing will progressively become faster and smoother.

Speech therapy will step the child through graded levels of production practice to ensure that they achieve sufficient success each time they practice. This not only helps children feel engaged and motivated, but also promotes motor learning. Home practice is an important part of successful speech therapy and will be reviewed and updated by the Speech Pathologist at every session. Games, toys and activities are used to keep kids engaged, while goals are constantly reviewed and adjusted to ensure that kids experience success and build confidence with their communication skills.

How should I support my child at home?

If your child is under 4 ½ years old and has an interdental lisp, you might like to have a go at practicing the sound by itself. For younger children, you might like to use games and play to make it more motivating. Try playing with snake puppets, drawing snake families or making playdough snakes who all say ‘sssss!’ For older children, try using a mirror to practise saying the ‘s’ sound. Encourage your child to watch your face, listen to your ‘s’ sound, and talk about how to use their tongue and mouth correctly e.g. “keep your tongue behind your teeth”. Making playdough teeth and tongues is also a great way to help kids understand how to move the tongue ‘behind’ vs. ‘between’ the teeth.

If your child has a lateral or palatal lisp, or is over the age of 4 ½ years, practising at home may not be sufficient for helping your child to successfully develop a clear ‘s’ sound. In this case, Speech Pathology advice is recommended to ensure that practise is helpful and successful.

When should I seek help?

If you have practised the ‘s’ sound at home for a few weeks but don’t seem to be getting anywhere, or if your child is becoming resistant or frustrated when you try to practise, help from a Speech Pathologist is recommended. Talking about speech and practising speech should never be a negative or frustrating experience for children. A Speech Pathologist can use specific techniques to make sure that practising speech is a positive, successful and confidence building experience.

For information about speech development and therapy, check out my website:

Brooke Miller – Business Director and Speech Pathologist


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