Minimal Speech is not Automatically Minimal Intelligence

When interacting with and assessing minimally speaking autistic children and adults, we have recognised a subgroup of autistic people whose spoken language is very limited, but whose intellectual ability and receptive language appear stronger than might initially be assumed. Emerging research is beginning to support our clinical observations. 

Nonverbal or Visual Intelligence 

Around 25-30% of autistic children do not develop functional speech and remain minimally speaking beyond the age of 5 (Anderson et al., 2007). Research suggests that within this group, some autistic children and adolescents show nonverbal reasoning abilities in the average range on standardised measures.   

For example, Guerrera et al. (2025), using the Leiter International Performance Scale, 3rd Edition, identified a subgroup of minimally speaking autistic children and adolescents whose non-verbal IQ scores fell within the average range.  Studies using Raven’s Coloured Progressive Matrices have also reported average-range nonverbal performance in some minimally speaking autistic children (Nikolaeva et al., 2019; Courchesne et al., 2019). Dempsey et al. (2018), using the Merrill–Palmer–Revised Scales of Development (M-P-R), similarly found that some minimally speaking autistic children showed relatively average nonverbal cognitive abilities. Yu et al. (2023) further noted that, for some minimally speaking autistic adults, nonverbal abilities can fall within typical limits on standardised assessment.  

Receptive language and reading 

Receptive language can also be stronger than expressive speech suggests. Studies have shown that some autistic children and adolescents with very limited speech demonstrate receptive language abilities that are higher than might be expected from spoken output alone (Chen et al., 2023; Muller et al., 2022).  

This has important implications for assessment. Many standard language tests assume that a person can respond by speaking or pointing. However, these response methods may underestimate comprehension if the autistic person has difficulty with motor planning or carrying out intentional goal-directed responses. 

A recent study by Ellert et al. (2025) used an eye-tracking task that did not require pointing or speech.  Minimally speaking autistic adolescents and adults were presented with spoken or written words, followed by two images, while their eye movements were recorded. The study found that 80% showed evidence of receptive language and reading abilities that were not captured by pointing responses alone. Interestingly, the same participants averaged only 57% accuracy when asked to point to the target image. The authors suggested that, for some autistic people, the main barrier may be less related to language comprehension and more related to producing the intentional motor responses required for communication, such as pointing or speech. 

Practical applications 

For professionals assessing minimally speaking autistic people, formal assessment should use multiple communication methods so that instructions, questions, and responses can be delivered and expressed across different modalities, rather than relying only on spoken language or pointing. Assessment should also explore nonverbal reasoning, receptive language, literacy, and alternative ways of demonstrating understanding. Doing so may lead to a more accurate understanding of a person’s strengths, support needs, and learning potential, and may help identify more appropriate communication approaches and therapeutic planning.   

It would also be helpful to know how common it is for autistic people with minimal speech to have motor difficulties that affect communication, either instead of, or alongside, language comprehension difficulties. Understanding how often this occurs could improve our knowledge of autism and inform more tailored assessment and intervention. If this profile can be identified accurately, practitioners may be better able to consider whether some people would benefit from referral to motor-based speech interventions where clinically indicated, for example approaches such as PROMPT (Chumpelik, 1984) for people with suspected speech motor difficulties, including apraxia-related presentations. 

Most importantly, we should not assume that a lack of speech automatically means a lack of intellectual ability or understanding. Minimally speaking autistic people deserve to be approached with respect, curiosity, and the presumption of competence. 

Masterclass Day 1: Assessment Beyond Diagnosis to Assist Minimally Speaking Autistic People 

Because speech alone may not reflect a person’s understanding, reasoning, or learning potential, assessment needs to go beyond surface impressions and broad assumptions. Our Masterclass Day 1 explores how to assess minimally speaking autistic people aged 6 and older beyond the autism diagnosis. It provides practical guidance on understanding abilities and behaviour, recognising mental health concerns, identifying medical and developmental factors, and selecting appropriate assessment tools that support more accurate and attuned understanding.  

https://www.attwoodandgarnettevents.com/products/webcast-masterclass-day-1-assessment-beyond-diagnosis-to-assist-nonspeaking-autistic-people-6-years  

References 

Anderson, D. K., Lord, C., Risi, S., Di Lavore, P. S., Shulman, C., Thurm, A., ... & Pickles, A. (2007). Patterns of growth in verbal abilities among children with autism spectrum disorder. Journal of consulting and clinical psychology, 75(4), 594.. doi: 10.1037/0022-006X.75.4.594 

Chen, Y., Siles, B., & Tager‐Flusberg, H. (2023). Receptive language and receptive‐expressive discrepancy in minimally verbal autistic children and adolescents. Autism Research, 17(2), 381–394. https://doi.org/10.1002/aur.3079 

Chumpelik, 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. https://doi.org/10.1055/s-0028-1085172 

Courchesne, V., Girard, D., Jacques, C., & Soulières, I. (2019). Assessing intelligence at autism diagnosis: Mission impossible? Testability and cognitive profile of autistic preschoolers. Journal of autism and developmental disorders, 49(3), 845–856. 

Dempsey, E., Smith, I., Flanagan, H., Duku, E., Lawrence, M., Szatmári, P., … & Bennett, T. (2018). Psychometric Properties of the Merrill–Palmer–Revised Scales of Development in Preschool Children With Autism Spectrum Disorder. Assessment, 27(8), 1796-1809. https://doi.org/10.1177/1073191118818754 

Ellert, K., Sykes-Haas, H. S., Shefer-Kaufmann, N., & Bonneh, Y. S. (2025). Hidden Literacy in Minimally Verbal Autistic Individuals Revealed by Eye Gaze. bioRxiv, 2025-11. 

Guerrera, S., Fuca, E., Petrolo, E., De Stefano, A., Casula, L., Logrieco, M. G., ... & Vicari, S. (2025). Exploring the clinical features of minimally verbal autistic children. Frontiers in Psychiatry, 16, 1549092. https://doi.org/10.3389/fpsyt.2025.1549092 

Muller, K., Brady, N., & Fleming, K. (2022). Alternative receptive language assessment modalities and stimuli for autistic children who are minimally verbal. Autism, 26(6), 1522–1535.https://doi.org/10.1177/13623613211065225 

Nikolaeva, E., Gaidamakina, M., & Zavodovskaia, D. A. (2019, May). ORIENTATION IN A SIGNAL FLOW AND INTELLIGENCE OF CHILDREN WITH AUTISTIC SPECTRUM DISORDERS. In SOCIETY. INTEGRATION. EDUCATION. Proceedings of the International Scientific Conference (Vol. 4, pp. 225–234). https://doi.org/10.17770/sie2019vol4.3894  

Yu, Y., Ozonoff, S., & Miller, M. (2023). Assessment of Autism Spectrum Disorder. Assessment, 31(1), 24–41. https://doi.org/10.1177/10731911231173089