How do you increase speech intelligibility (articulation skills) or the variability in the sounds produced by children with autism spectrum disorders?

Answered by Tracie L. Lindblad, Reg. CASLPO (SLP), MS, MEd, BCBA

Approximately 30-50% of individuals with Autism Spectrum Disorders (ASDs) remain minimally verbal throughout their lives, with little or no functional speech (National Institutes of Health & National Institute on Deafness and Other Communication Disorders, 2010; Johnson, 2004; Mirenda, 2003). These individuals may rely on more effortful modes of communication such as reaching for desired items, taking another’s hand to gain access, or obtaining the item independent of communication. Attempts to communicate may also take the form of challenging behaviors such as aggression, self-injury, and tantrums.

Parents face a difficult task in choosing a treatment for minimally verbal children with ASDs because a wide range of techniques are routinely used by speech-language pathologists and behavior analysts with varying degrees of success and evidence.

The following table highlights some of the most commonly implemented interventions to target speech skills and the current evidence base for each.

TreatmentBrief DescriptionEvidence
Articulation Therapy
  • A sequence of therapy where the target sound is practiced first in isolation, then in syllables, words, sentences, stories, conversation, and finally, in generalized to all contexts of language
  • Sound errors are usually targeted in the order that they occur in typically developing children
  • Some limited evidence with results from quasi-experimental studies (single case design, multiple baseline studies, etc.) and non-experimental studies (descriptive reports, case studies, etc.)
  • More rigorous research is needed in order to compare the relative benefits of different intervention approaches (Baker & McLeod, 2011)
Echoic Training
  • The use of strategies based on applied behavior analysis (ABA) to shape better productions of specific sounds and words
  • Similar to articulation therapy in that it works on repetition of sounds
  • Good evidence but results are highly variable across children with some making substantial progress in their speech while others do not (Ross & Greer, 2003)
Kaufman Speech Praxis Treatment approach (Kaufman, 1998)
  • A manualized systematic method of shaping speech sound combinations that follows a defined developmental progression
  • This intervention was developed specifically for children with developmental apraxia of speech
  • Insufficient evidence for children with ASDs; results from non-experimental studies (descriptive, case series, etc.) and expert opinion evidence only
  • More research is needed (Morgan & Vogel, 2008)
Mand (request) Training
  • The use of echoic training/speech shaping within the context of a request in order to capitalize on the child’s motivation to communicate (i.e., the child receives the item that he/she requests)
  • In other words, the reward for saying the sound/word/phrase is obtaining that item, unlike echoic training or articulation therapy where the ‘reinforcer’ is not generally related to the target sound/word
  • Good evidence to support use of this procedure
  • Child response to this approach can also be variable (Sherer & Schreibman, 2005)
Oral-Motor Imitation Training (Rosenfeld-Johnson, 2001; Marshalla, 2009)
  • An approach which uses imitation training to increase non-speech movements and sounds such as puckering the lips, blowing, moving the tongue rapidly, etc
  • Tools such as Nuk® brushes, tongue depressors, and whistles/straws of varying diameters may be used as prompts/aids to assist the placement of the lips, teeth, tongue, and jaw
  • No effectiveness demonstrated in any well-designed study non-experimental studies (descriptive, case studies, etc.) conducted; however, there is a growing number of studies to substantiate that there is no effect (McCauley, Strand, Lof, Schooling, & Frymark, 2009)
PROMPT Method (Prompts for Restructuring Oral Muscular Phonetic Targets) (Chumpelik [Hayden], 1984)
  • A manualized tactile-kinesthetic approach that uses touch cues to a student’s jaw, tongue, and lips to manually guide the production of a target word
  • Thought to help develop motor control and proper oral muscle movements
  • Insufficient evidence for children with ASDs
  • No research with individuals with ASDs conducted by independent labs/researchers (Pace, 2011)

Within the fields of behavior analysis and speech pathology, evidence-based practice (EBP) should shape and guide our treatment decisions. EBP is the integration of:

  • external scientific evidence
  • clinical expertise/expert opinion, and
  • client/patient/caregiver perspectives

Principles of EBP can help any professional to provide high-quality services which reflect the interests, values, needs, and choices of the individuals, and promote the best outcomes possible with the current evidence to date.

Therefore, treatment decisions should take into account a number of factors such as:

  • current level of evidence
  • learner characteristics (such as initial echoic repertoire)
  • motivation of the child
  • response to imitation-type programs
  • training and background of the professional/team (e.g., early intensive behavioral intervention (EIBI) team, speech-language pathologist (SLP), paraprofessional, etc.)
  • intensity of the planned intervention

Working as a collaborative team comprised of behavior analysts, early interventionists, and SLPs will allow the development of appropriate targets by drawing on the specific strengths from each profession. Speech-pathologists are trained in the developmental acquisition of speech sounds and in the selection of appropriate substitutions or simplification of speech sounds in order to help the student progress from easier targets to more difficult ones. On the other hand, behavior analysts are uniquely trained in using shaping procedures effectively, assessing motivation to assist in learning, and collecting of detailed and specific data to guide treatment decisions. With a collaborative team, the child benefits from a well-designed program with appropriate targets.

When guided by the current evidence for treatment and the clinical expertise/knowledge from the fields of ABA and speech pathology, the following sequence may be helpful in designing a program to target echoic/speech production skills:

  1. Conduct an initial assessment of the child’s sound productions. This may be completed by an SLP using standard articulation or phonological tests or by a behavior analyst using assessment tools such as the Assessment of Basic Language and Learning Skills—Revised (ABLLS-R; Partington, 2006) or Verbal Behavior Milestones Assessment Placement Program (VB-MAPP; Sundberg, 2008), which includes the Early Echoic Skills Assessment (EESA; Esch, 2008).
  2. Compile a list of items and activities that the child would typically be motivated to request on a daily basis. Determine appropriate word approximations or the shaping steps for each of the words.
  3. Set up opportunities throughout the day for the child to request these preferred items/activities; in order to practice the target sounds/words. Some of these may be already occurring; however, it is often necessary to create additional opportunities and to ensure that the request is reinforced when it occurs.
  4. Record the frequency and accuracy of the child’s production in order to determine when a more complex target will be required (i.e., shape the sound/word to a more ‘typical’ production).
  5. Prompts or cues may be added to the practice trials to help the student meet the targeted production. These prompts will need to be systematically faded so that the student learns to accurately produce the sound/word independently.
  6. Difficult targets should also be practiced within the context of an echoic program where the child is given additional opportunities for practice. Systematic and frequent teaching, prompting, and reinforcement are key elements in changing the behavior.
  7. A planned effort to promote the generalization of all targets outside of the structured sessions is critically important.
  8. Continue to assess the intelligibility of the child in order to ensure that vocal speech is functional. If the child is not understood by an unfamiliar listener at least 80% of the time, then an augmentative and alternative communication (AAC) system such as the Picture Exchange Communication System (PECS, Bondy & Frost, 2001) should be considered while speech skills continue to develop.


Baker, E., & McLeod, S. (2011). Evidence-based practice for children with speech sound disorders: Part 1 narrative review. Language, Speech, Hearing Services in Schools, 42, 102-139.

Bondy, A., & Frost, L. (2001). The Picture Exchange Communication System. Behavior Modification, 25, 725-744.

Chumpelik (Hayden), D. A. (1984). The PROMPT system of therapy: Theoretical framework and applications for developmental apraxia of speech. Seminars in Speech and Language, 5, 139-156.

Esch, B. (2008). Early Echoic Skills Assessment. In Sundberg, M. (2008). VB-MAPP: Verbal Behavior Milestones Assessment and Placement Program A Language and Social Skills Assessment Program for Children with Autism Or Other Developmental Disabilities: Guide.

Johnson, C. P. (2004). Early clinical characteristics of children with autism. In V. B. Gupta, Autistic spectrum disorders in children (pp. 96-134). New York: Marcel Dekker.

Kaufman, N. (1998). Kaufman speech praxis treatment kit for children. Gaylord, MI: Northern Speech Services.

Marshalla, P. (2009). Improving Intelligibility in Apraxia and Dysarthria. Mill Creek: Marshalla Speech and Language.

McCauley, R. J., Strand, E., Lof, G. L., Schooling, T., & Frymark, T. (2009). Evidence-based systematic review: Effects of nonspeech oral motor exercises on speech. American Journal of Speech-Language Pathology, 18, 343-360.

Mirenda, P. (2003). Toward functional augmentative and alternative communication for students with autism: Manual signs, graphic symbols, and voice output communication aids. Language, Speech, and Hearing Services in Schools, 34, 203-216.

Morgan, A. T., & Vogel, A. P. (2008). Intervention for childhood apraxia of speech. doi:10.1002/14651858.CD006278.pub2

National Institutes of Health & National Institute on Deafness and Other Communication Disorders. (April 13-14, 2010). NIH workshop on nonverbal school-aged children with autism. Retrieved from

Pace, J. (2011). Critical Review: Is PROMPT an effective treatment method for children with speech production disorders? Retrieved from

Partington, J. (2006). The assessment of basic language and learning skills-revised (The ABLLSTM-R): An assessment, curriculum guide, and skills tracking system for children with autism or other developmental disabilities. Pleasant Hill, CA: Behavior Analysts, Inc.

Rosenfeld-Johnson, S. (2001). Oral-motor exercises for speech clarity. Tucson, Arizona: Innovative Therapists International.

Ross, D. E., & Greer, R. D. (2003). Generalized imitation and the mand: Introducing first instances of speech in young children with autism. Re-search in Developmental Disabilities, 24, 58-74.

Sherer, M. R., & Schreibman, L. (2005). Individual behavioral profiles and predictors of treatment effectiveness for children with autism. Journal of Consulting and Clinical Psychology, 73, 525-538.

Sundberg, M. L. (2008). VB-MAPP: Verbal Behavior Milestones Assessment and Placement Program: Guide. Concord, CA: AVB Press.

Citation for this article:

Lindblad, T. L. (2012). Clinical corner: How do you increase speech intelligibility (articulation skills) or the variability in the sounds produced by children with autism spectrum disorders? Science in Autism Treatment, 9(3), 3-6.

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