What Is A Lisp

About lisp

At dinner parties, lunches (or even on the occasional date), I get asked what I do for work. Typically the conversation involves the explanation of the difference (or lack of difference) between a speech pathologist and speech therapist and the person asking “So you work with people who stutter or lisp?” Lisps tend to be the most ‘well-known’ speech difficulty, but what exactly is a lisp?

What is a lisp?

A lisp is an articulation disorder. It occurs when a child is having difficulty producing the‘s’ or ‘z’ sounds. Sometimes children with a lisp also have difficulty producing other related sounds such as ‘sh’ ‘ch’ and ‘j’.

What causes a lisp?

There is no definitive cause of a lisp. Some speech and language professionals hypothesise that lisps are caused by a form of muscle weakness, others disagree. In some cases, a lisp is associated with a ‘tongue thrust’. A tongue thrust is a swallowing pattern that causes the tongue to push too far forward during swallowing. This can affect a child’s speech. If you have concerns about your child’s swallowing or are concerned about a tongue thrust, you should consult your regular medical provider. A speech pathologist can assist in determining if your child has a tongue thrust.

Is there more than one kind of lisp?

Yes, there are four types of lisps. Each refers to differences in where the sound is produced in the mouth and how the air flows when producing the sound. The ‘s’ and ‘z’ sounds are normally produced in the same place in the mouth: the tongue sits behind the teeth and the sides of the tongue are raised to touch the upper molars. This creates a channel for the air to flow through when producing the sound. The four kinds of lisps are outlined below:

1. Interdental lisps: This occurs when your tongue goes between your front teeth and makes a ‘th’- sound for the‘s’ and ‘z’ sounds. Examples include saying ‘thwam’ for ‘swam’ or ‘thoup’ for ‘soup’. This kind of lisp is considered a part of normal speech development until a certain age.
2. Dentalized lisps: This occurs when the tongue touches the teeth while making the ‘s’ and ‘z’ sounds). This kind of lisp is considered a part of normal speech development until a certain age.
3. Lateral lisp: This occurs when air escapes out the sides of the tongue. This kind of lisp is not usually seen in typical speech sound development. A child is less likely to ‘grow out of’ this kind of lisp.
4. Palatal lisp: This occurs when the tongue hits the soft palate while making the ‘s’ and ‘z’ sound. As with the lateral lisp, a palatal lisp is not usually seen in typical speech sound development. A child is less likely to ‘grow out of’ this kind of lisp.

For further explanation of these four types, a great resources is Caroline Bowen’s article found here: Caroline Bowen’s website

When should my child have ‘grown out of a lisp’?

As mentioned above, a lateral and palatal lisp is not considered part of typical speech development and should therefore be assessed by a speech pathologist as soon as possible. A speech pathologist will be able to assess and discuss options for intervention. Intervention for lateral and palatal lisps can be a little tricky, so depending on a child’s ability to follow directions and participate in therapy, therapy could start around the age of three to four.

In terms of interdental and dentalised developmental lisps, there is much discussion in SLP circles and within literature regarding the age in which these lisps are no longer considered to be developmentally appropriate. Some developmental norm sets indicate that mastery of the‘s’ and ‘z’ occurs closer to 7-8 years of age (Sanders, 1972). The Goldman Fristoe Test of Articulation presents developmental data that indicates the most children had mastered the ‘s’ sound by 5 years of age (Goldman & Fristoe, 2000). Some expert speech pathologists recommend that if the lisp persists beyond 4.5-5 years of age, intervention is warranted (Bowen, 2012).

If I’m concerned about my child’s speech, what can I do?

If you are concerned that your child has a lisp, or has difficulty producing other speech sounds it is recommended that you see a speech pathologist. A speech pathologist is able to determine the nature of a lisp, and whether or not it is appropriate for his/her age.

Speech assessments generally entail completing a detailed case history, an examination of the mouth structures and movements and sampling a child’s speech and language. A speech pathologist will generally screen other areas of communication development also. This may include language, voice, fluency and social skills.

If your child has a lisp and is requiring speech therapy, a speech pathologist will establish an intervention plan according to the needs of your child. Some children respond very quickly to therapy, others require longer to master specific sounds.

Results focused speech therapy in Sydney

This article was written by our speech pathologist, Jenna Butterworth, who is a Speech Pathology Australia member.

If you have questions about a lisp or other difficulties with speech, contact your local doctor who will arrange for you to see a speech pathologist in Sydney. Contact us today!

For more information about articulation disorders see Jenna’s article Articulation vs Phonological speech errors.