Errors in speech are commonplace since speech production is a complex activity. Young children who are still acquiring mastery of speech and language can make many speech errors. For example, they sometimes speak with assimilation (i.e. consonant harmony), making the beginning and ending consonants the same sound (e.g. if a child says ‘beb’ for ‘bed’ or ‘lellow’ for ‘yellow’). Children with autism also make errors in speech. However, over time, they might not be self-correcting as this is usually the case in typically developing children.
Even though there are findings to suggest that children with autism display symptoms characteristic of some oral motor disorders, it would be misguided to make the claim that oral motor issues cause speech impairments in them. To build an understanding of the speech difficulties facing children with autism, the first section expounds on what it means to speak from the pathological perspective. Next, we will look at the patterns of errors in speech made by a child with autism and if that points to particular oral motor issues. In the concluding section, we will discuss the clinical significance of the presentation of oral motor issues in a child with autism, and how that could better inform speech and language interventions.
Process of Speech
Speaking is an act that can be said to have two broad components ― mental (i.e. neurological) and physical (i.e. oral musculature). Part of the mental process of speaking involves the selection of functional words from the speaker’s lexicon and the organisation of those words into the appropriate syntax. Then, the words with their phonetic properties are articulated.
To be able to articulate speech sounds is to be able to execute airflow and to physically coordinate the oral placement of lips, tongue and jaw in a precise manner. The speech production process in typically developing children goes as such: First pressure is produced from the lungs, which creates phonation in the glottis. It is then modified by the vocal tracts and the mouth region into various vowels and consonants. Finally, the specific arrangement of vowels and consonants make up speech sounds with distinct phonetic qualities.
Oral motor disorders arise from a disturbance in the process of speech. Specifically, oral motor disorders could stem from a neurological impairment, i.e. an inability to execute motor movements needed for speech ― in the case of apraxia of speech (AoS) or developmental verbal dyspraxia (DVD) ― or a weakness in oral musculature, in the case of dysarthria. In the following section, we will look at the patterns of errors in speech made by the autism population and if that points to AoS/DVD or dysarthria.
Speech Difficulties in Children with Autism
Although not many studies on speech production of children with autism have found consistent results, there is some consensus that these children display atypical prosodic features in early vocalisations. For example, a study found that children with autism (aged 4- to 10-year-old) were observed to have exaggerated pitch, pitch range, pitch excursion and pitch contours compared to age-matched typically developing children (Sharda et al., 2010). The atypical prosody observed are characteristic of ‘motherese’, which is speech directed to infants bearing higher pitch, slower tempo and exaggerated intonation. Typically developing children also exhibit motherese-like features, but they outgrow it by 2 to 3 years old.
Another study found that 12% of children with high-functioning autism presented with scores below the normal range on a standard test of articulation, indicating the presence of a speech disorder (Cleland, Gibbon, Peppé, O'hare, & Rutherford, 2010). Aside from deviation in articulation, the same study also found that almost half of the group produced developmental speech errors in phonation like final consonant deletion, cluster reduction and gliding. To give an example for gliding, these children would say ‘wun’ for ‘run’ or ‘yego’ for ‘lego’, replacing beginning consonants with ‘w’ or ‘y’.
Taken altogether, there has been some evidence to suggest that some children with autism display symptoms characteristic of oral motor disorders ― in particular, they have challenges correctly articulating words with complex phonemic combinations and multiple syllables. In addition, the speech production of the children with autism may contain syllable deletions, voicing errors, and consonant and vowel distortions (Adams, 1998). Problems such as these are most often associated with the oral motor disorder AoS/DVD.
It is important to note that even though past research has shed some light on the speech atypicalities in autism, no clear patterns have emerged to definitively establish children with autism as having a specific speech disorder due to the heterogeneity of the disorder and variability in measurements used.
Possible Speech Interventions for Children with Autism Presenting with Oral Motor Issues
Children with autism who also present with oral motor issues are challenging for the speech language pathologist. If the child with autism displays articulation problems and is not responsive to traditional speech therapy, the clinician could consider assessment and intervention that focuses on the adaptation of motor planning and programming.
The tenets of motor planning and programming include the following:
high rate of repetition through drill,
systematic progression through hierarchy of task difficulty,
emphasis on self-monitoring,
multiple input modalities,
manipulation of prosodic features,
teaching of compensatory strategies; and
provision of successful experiences (Hall et al., 1993)
To sum it up, though there is no established definitive evidence pinpointing oral motor issues as a cause of speech impairments in children with autism, it would be beneficial to develop autism-friendly interventions designed for children with autism who also present symptoms of AoS/DVD in order to induce spoken language.
Written by Jacelyn Lee.
Sharda, M., Subhadra, T. P., Sahay, S., Nagaraja, C., Singh, L., Mishra, R., . . . Singh, N. C. (2010). Sounds of melody—Pitch patterns of speech in autism. Neuroscience Letters, 478(1), 42-45. doi:10.1016/j.neulet.2010.04.066
Cleland, J., Gibbon, F. E., Peppé, S. J., O'hare, A., & Rutherford, M. (2010). Phonetic and phonological errors in children with high functioning autism and Asperger syndrome. International Journal of Speech-Language Pathology, 12(1), 69-76. doi:10.3109/17549500903469980
Adams, L. (1998). Oral-Motor and Motor-Speech Characteristics of Children with Autism. Focus on Autism and Other Developmental Disabilities, 13(2), 108-112. doi:10.1177/108835769801300207
Hall, P., Jordan, L., & Robin, D. (1993). Developmental apraxia of speech: Theory and clinical practice. Austin, TX: PRO-ED.