Childhood Apraxia of Speech (CAS)

What is Childhood Apraxia of Speech and how does Speech Therapy help?

Childhood Apraxia of Speech (CAS) is also commonly known as verbal apraxia, developmental apraxia of speech, or verbal dyspraxia. CAS is a severe permanent and lifelong disorder of speech motor programming and planning which is present from birth and does not naturally resolve .1 This is very frustrating for the speaker as they know what they’re trying to say, but the motor program impacts their coordination impacting the clarity of speech. This is often initially described by parents as their kids jumbling up sounds, or having mumbly speech

There is currently no known cause for CAS, however it can co‐occur with other speech, language, literacy, and developmental disorders. The prevalence of CAS is low, generally affecting one to two children per thousand (0.1% of the child population).2 CAS has increased frequency in children and adults with galactosaemia, epilepsy, or Down Syndrome but has no increased prevalence in autistic children.1

Signs and Symptoms of Childhood Apraxia of Speech

For a child to receive a diagnosis of CAS, they must meet all three consensus‐based features of CAS: 3

  • Inconsistency across words and syllables
  • Lengthened and disrupted coarticulatory transitions
  • Inappropriate prosody

Inconsistency across words and syllables refers to the difficulties of repeating words in the same way. In CAS, typically there are more errors in consistency with longer words compared to shorter words. For example, the word ‘caterpillar’ may be said as: “catepita, petakilla, patepilla.” This is different from other types of speech sound errors where a sound error is consistently said incorrectly. For example in a lisp the /s/ sound is articulated as /th/, sun→ ‘thun’, house →’ houth’. In CAS, the motor programing interferes with the correct articulation of the word leading to inconsistency errors.

Coarticulatory transitions refers to the ability to transition smoothly and in a timely manner between sounds in a word. This may look like pauses between syllables (e.g. butter…fly), pauses between sounds (e.g. caterp…illa), false starts, hesitations, repairs, repetitive attempts (groping) and lengthened sounds (e.g. mosssman). This often means that children’s speech can sound ‘choppy’ on certain vowels or consonants.

Prosody refers to the stress pattern within words (e.g. te-le-scope) and within sentences (e.g. the man had a blue shirt). The stress pattern for children with CAS may be altered or made equal. This also impacts their intonation which is the natural rise and fall of conversation.

The impact of CAS on a child’s development

CAS can impact a child in areas other than speech sounds. Research shows that children with CAS have lower scores in language skills compared to children without CAS. Children with CAS also presented with comorbid reading, spelling, and academic difficulties at school age.4 More specifically, children with CAS struggle with phonological awareness tasks. These are the foundational tasks for literacy and include sound identification, segmentation and blending of sounds. Children with CAS particularly have difficulty with segmenting the sounds in words (e.g. b-u-tt-er). This is because they have difficulty consistently and accurately saying the sounds in words.

Children with CAS can also experience social difficulties. Research states that their experiences of social learning and play is “made endlessly more complicated by early and ongoing communicative challenges impacting social experience and social encounters”5. As well as improving their speech and communication skills, supporting children with CAS in understanding and managing their emotions can be helpful for them in navigating their play and social experiences.

Apart from speech therapy, children with CAS may benefit from the following supports:

  • Occupational Therapy – to help them with motor tasks, such as fine and gross motor skills, as well as emotional regulation
  • Psychology – especially if their difficulties expressing themselves impact their confidence or self-perception

What happens in an assessment for Childhood Apraxia of Speech?

A comprehensive speech pathology assessment is needed in order to confirm a diagnosis of CAS.3, 6 During an assessment a Speech Pathologist will undertake:

  • Case History: discussing with parents their concerns, the child’s developmental history, performance at school etc. is essential to the diagnostic journey for CAS
  • Oral motor assessment: these non-speech activities observe how a child moves their lips, tongue and jaw in activities such as blowing, smiling and kissing.
  • Speech production: the child’s ability to make sounds, words and sentences will be observed throughout the assessment. They may be asked to name pictures, to give a verbal recount or to copy the clinician’s words.
  • Motor Planning: repeating sounds (e.g. p-p-p-p-p) and syllables (e.g. pa-ta-ka, pa-ta-ka) help to see if a child can quickly transition between sounds accurately and consistently,
  • Prosody: observing their melody and rhythm of speech, such as how they stress syllables and words
  • Language and Literacy skills: children with CAS may also have other language and/or literacy needs. Development of literacy skills can be impacted as children struggle with accurately sounding out words, equally or because the way they say a a word is not accurate impacts their spelling.
  • Hearing: it is essential that children receive a hearing test prior to their speech pathology assessment to rule out any hearing impairment contributing to their speech difficulties

Once a child receives a diagnosis of CAS, they are elligible for National Disability Insurance Scheme (NDIS) funding. This is because CAS is a life-long condition that requires speech therapy treatment. Speech Pathology Assessment Reports can be an essential document to help secure this funding.

Speech Therapist assisting child with Childhood Apraxia of Speech

Our FREE Discovery Session is ideal for anyone with any questions relating to speech, stuttering, language, literacy, social skills, swallowing, and voice.

This is an opportunity for us to give some information on how to monitor your concern and give you advice on how to start self-managing any issues immediately.

Discovery Sessions can help you understand if an assessment or therapy is needed, how Speech Therapy would work, and if appropriate, help you book in.


1McCabe, P., Murray, E. & Thomas, D. (January 2020). Evidence Summary ‐ Childhood Apraxia of Speech.

2Shriberg, L.D., Aram, D.M., & Kwiatkowski, J. (1997). Developmental apraxia of Speech. I. Descriptive and theoretical perspectives. Journal of Speech, Language, and Hearing Research, 40, 273–285. doi:10.1044/jslhr.4002.273

3American Speech-Language-Hearing Association. (2007). Childhood apraxia of speech [Technical Report].

4Lewis, B. A., Freebairn, L. A., Hansen, A. J., Iyengar, S. K., & Taylor, H. G. (2004). School-age follow-up of children with childhood apraxia of speech.

5Tarshis, N., Winner, M. G., & Crooke, P. (2020). What does it mean to be social? Defining the social landscape for children with childhood apraxia of speech. Perspectives of the ASHA Special Interest Groups, 5(4), 843-852.

6Murray, E., McCabe, P. Heard, R. & Ballard, K.J. (2015). Differential Diagnosis of children with suspected Childhood Apraxia of Speech. Journal of Speech, Language and Hearing Research 58, (1) 43‐60.


8McCabe, P., Thomas, D., Murray, E., Crocco, L., & Madill, C. (2017). Rapid Syllable Transition Treatment – ReST The University of Sydney. Retrieved from (download date: 27th June 2022)

9Murray, E. McCabe, P., & Ballard, K.J. (2015). A randomized controlled trial for children with childhood apraxia of speech comparing Rapid syllable transition treatment and the Nuffield Dyspraxia Programme (3rd edition). Journal of Speech, Language & Hearing Research, vol 58 (3), 669-686.

10Williams, P., & Stephens, H. (2010). The Nuffield Center Dyspraxia Programme. In A. L. Williams, S. McLeod, & R. J. McCauley (Eds.), Interventions for speech sound disorders in children (pp. 159–178). Baltimore, MD: Brookes.