Lisp

A lisp is one of the most common speech problems we work with in speech pathology.

A ‘lisp’ is a lay-term often used to describe difficulty achieving the correct placement of the tongue to create clear, easy to understand “s” and “z” speech sounds. This may or may not be accompanied by the tongue poking out.

Lisps are a common type of ‘functional’ speech disorder (FSD)^[1]. This means a difficulty making one specific speech sound or several specific speech sounds.  It is ‘functional’ because the root cause of the disorder is not entirely clear. These can persist into the teenage or adult years. However, they can be successfully treated with speech therapy.

A lisp most likely has a phonetic origin, meaning a child has a difficulty physically achieving the correct placement of their lips, tongue and/or jaw to create clear, easy to understand speech sounds. Fortunately, this does not mean we cannot fix it.

This is different from other types of speech sounds disorders which we know have a linguistic origin, meaning that they can usually make the individual speech sounds but have difficulty working out which one to use, especially when they are similar to another sound. Those types of speech sound errors are phonological disorders (linguistic in origin).

It is not uncommon for a child to have both a functional speech sound disorder and a phonological speech sound disorder.

There may also be physiological factors contributing to a lisp. Ear Nose and Throat specialists (ENTs) are unable to rule out the contributions of enlarged tonsils at a young age or nasal obstructions (snuffly breathers or children with allergies) towards a lisp^[2]. The reasoning behind this is that enlarged tonsils (whether infected of not) take up much of the space at the back of the throat where the base of the tongue would normally sit pushing the tongue into a more forward position. This can often be associated with ‘mouth breathing’, where the mouth may rest open rather than closed due to the position of the tongue. The same is true for children with nasal allergies or narrowing of the nasal passages as they may compensate by being mouth-breathers^[3][4]. Parents will often tell us their child has a large tongue but this is rarely ever the case. These children do, however, appear to dribble more frequently. This may be due to them swallowing their saliva less frequently.

Orthodontists and Dentists agree that genetics plays a large role in the shape of your jaw and bite. However, the shaping of the jaw and subsequently the teeth positioning is also strongly influenced by the surrounding soft tissues and muscular forces of your tongue and lips and cheeks. So, a latent ‘tongue thrust’ where your tongue pushes forward slightly on swallowing can contribute to an ‘overbite’ where your top teeth are pushed further forward in relation to the lower teeth. In these children and adults we often also see ‘lisp’ speech behaviours. However, we have to treat the underlying tongue thrust behaviours first.

There are four types of lisp: interdental, lateral, palatal and dentalised. The most common lisp is the interdental lisp. An interdental lisp occurs when a child tries to say “s” and/or “z” speech sounds with the tongue sticking out between the teeth. This results in a “th” speech sound instead of a “s” or “z” speech sound.

Then we have the dentalised lisp, which occurs when a child pushes the tip of their tongue up against their front teeth, resulting in a muffled “s” or “z” speech sound.

The next most common lisp is the lateral lisp. A lateral lisp occurs when air is directed over the sides of the tongue instead of down the middle and over the tip of the tongue for “s” and/or “z” speech sounds. This results in a slushy “s” or “z” speech sound.

The palatal lisp is less common. A palatal lisp occurs when a child tries to say “s” and/or “z” speech sounds with the tongue touching the soft palate (the roof of the mouth).

Interdental lisps are common among children learning to talk. Both interdental and dentalised lisps can be a normal part of a child’s speech development, and resolve as the child matures. However, if you think your child has an interdental or dentalised lisp, and they are 4 ½ years of age or older, we recommend you contact us at Talkshop Speech Pathology.

In contrast to interdental and dentalised lisps, lateral and palatal lisps are not considered to be a normal part of a child’s speech development. If you think your child has a lateral or palatal lisp, and they are 4 years of age or older, we recommend you contact us at Talkshop Speech Pathology^[5].

Lisps can persist into adulthood if the adult did not attend speech pathology as a child or if they discontinued speech pathology prematurely.

Some adults are not worried about having a lisp. Some adults may even see having a lisp as being a positive part of their identity. In this case there is no need to attend speech pathology. Other adults may feel embarrassed, frustrated or simply annoyed about having a lisp. If you feel this way, it is probably a good idea to contact us at Talkshop Speech Pathology. It is not too late for us to help you out!

Assessment for a lisp at Talkshop involves formal and informal assessment of your child’s speech skills, and pre-literacy/literacy skills, as we know that having a speech sound disorder places a child at risk for having literacy difficulties. It involves an oromotor assessment, meaning an assessment of the structure and function of your child’s lips, tongue, mouth and jaw, to ensure that they have the physical ability to create clear speech sounds. In addition, it involves informal assessment of your child’s language skills.

Therapy for lisps involves teaching a hierarchy of skills. The hierarchy usually moves from your child saying the “s” and “z” speech sounds in isolation, to your child saying “s” and “z” independently in all contexts of their everyday life. The steps in between vary according to your child’s strengths and weaknesses, as do the techniques used to help your child understand what they are doing wrong and how to make it right at each step. Examples of techniques used include visual cues (e.g. modelling how the speech sound looks, using gestures to represent speech sounds), verbal cues (e.g. modelling how the speech sound sounds, providing verbal instructions), and tactile cues (e.g. showing the child where to place their lips/tongue/jaw using touch).

Therapy for tongue thrusts also involves teaching a hierarchy of skills. As tongue thrust is a learnt motor pattern (the pattern of movement our brain instructs our muscles to move in) it requires a period of therapy to out-train your child’s old habitual way of using their tongue for speech and swallowing. The way that your child uses their tongue for swallowing will need to be targeted before their interdental lisp can be targeted.

We always provide parent training within therapy sessions so that you feel confident completing home practice tasks with your child each week. This is a high priority for us as we know that frequency of practice is so important for your child’s progress.

Last but not least, therapy involves finding the right balance of challenging and fun to keep you and your child motivated.

If you are unsure if your child has a lisp, book in a free initial phone consultation or a face-to-face consultation at our Free Friday Community Clinic.

Read more about how Talkshop Speech Pathology treats speech delays and speech disorders