A lisp is one of the most common speech problems we work with in speech pathology.
How speech pathology can treat a lisp
What is a lisp?
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). 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.
What causes lisps?
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. 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. 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.
1 “speech language therapy – Caroline Bowen.” 23 Nov. 2011,
https://www.speech-language-therapy.com/index.php?option=com_content&view=article&id=86:lisp. Accessed 14 Jan. 2019.
2 “Tonsils, Adenoids, tongue tie | ENT Specialists.”
http://entspecialists.com.au/services/tonsils-and-adenoids/. Accessed 14 Jan. 2019.
3 “The effects of adenoidectomy and tonsillectomy on speech and nasal ….”
https://www.ncbi.nlm.nih.gov/pubmed/15087574. Accessed 14 Jan. 2019.
4 “Effects of tonsillectomy on speech and voice. – Semantic Scholar.”
https://www.semanticscholar.org/paper/Effects-of-tonsillectomy-on-speech-and-voice.-Mora-Jankowska/737d2d983e1f557b9def3cec9866f0d6d2b49df4. Accessed 14 Jan. 2019.
5 “Fact Sheets – Speech Pathology Australia.”
https://www.speechpathologyaustralia.org.au/SPAweb/Resources_for_the_Public/Fact_Sheets/Fact_Sheets.aspx. Accessed 14 Jan. 2019.