The mother of an especially loquacious 8 year 7 month old boy diagnosed with an autism spectrum disorder recently asked me if it were really true many kids with autism are non-verbal. She had heard about a study indicating that was the case, which was difficult to believe in light of her son’s development. When I first began working in this field it was usually said that about three-quarters of pre-school and school age kids with autism had no functional speech. A recent collaborative multi-site project by Autism Speak’s a High Risk High Impact Initiative
indicates about 25% of children with an ASD diagnosis are now said to be functionally non-verbal. They likely vocalize and may say some words, but seldom if ever use them to actually communicate.

Most children who are functionally non-verbal fall into the category Dr. Judith Miles and her colleagues refer to as Complex Autism. Individuals in whom there is evidence of some abnormality of early tissue development, including either differences in such things as tooth, ear or eyebrow placement, missing crease in one hand, or unusual head hair whorls. Many also have unusually large or small head size. These individuals have more seizures and brain wave abnormalities as well as structural brain imaging test differences. Children and youth with Complex Autism usually have IQs under 55 and often have no functional speech. Complex Autism is less likely to run in families than Essential Autism, where those differences are absent.

Most children with Essential Autism have difficulty and delays in developing spoken language, with the exception with youngsters with Asperger Disorder, who occur in about 1:300 births. Many children with Asperger Disorder develop speech precociously, often using vocabulary well beyond their chronological or even intellectual age. Most of the remainder of children with Essential autism develop functional speech laboriously, often only with special assistance from speech language pathologists and behavioral intervention specialists. While there is a great deal known about promoting speech development in about 70-75% of children with autism, those with Complex Autism pose special challenges. Early Intensive Behavioral Intervention has enabled over half of those children with profiles similar to Essential Autism to develop language skills approximating their typical peers.

The Autism Speaks High Risk High Impact Initiative was faced with first defining what is meant by “non-verbal,” since some children say words, but do not use them in practical ways to communicate. Typically such individuals who are truly not able to verbally communicate have been taught using various augmentative communication systems, like the Picture Exchange System or speech output devices. Many times these approaches are combined with efforts to promote spoken communication concurrently. There is interest in the fact that among a subset of such non-speaking individuals there may, nonetheless, be considerable reciprocal social interest (e.g. John Canstantio at Washington University), which may be an important source of communication motivation.

Most experts believe cognitive ability and verbal communication are inter-twined, so those individuals with lesser cognitive abilities are likely to be especially challenged. Hopeful brain imaging research may shed light on subtypes of individuals with varying degrees of neurocognitive processing upon which therapists may capitalize in promoting communication development. In addition work on animal models is attempting to clarify alternative social pathways that may be beneficial in promoting socialization in non-speaking individuals.


Autism and Communication; National Institute of Deafness and Other Communicative Disorders. National Institutes of Health. NIH Pub. No. 09-4315; July 2009

Autism Speaks (2008) Researchers Focus on Non-Verbal Autism at High Risk High Impact Meeting;

Miles, JH et. al. (2005) Essential versus complex autism: definition of fundamental prognostic subtypes.
Am. J. Med. Genet. A. 135(2): 171-80

Paul, Rhea (2010) Yale Laboratory of Developmental Communication Disorders. Yale Child Study Center,

Sallows, GO and Graupner, TD (2005) Intensive Behavioral Treatment for Children WithAutism: Four-Year Outcome and Predictors.
Amer. J. Mental Retardation 110, 6: 417–438

Tager-Flusberg, H. (2009) Defining Spoken Language Benchmarks and Selecting Measures of Expressive Language Development for Young Children With Autism Spectrum Disorders.
J. Speech Lang Hear Res 52: 64. Published On-line 29 April 2009.