Home » Nonverbal Autism and Communication Skills » What is Idiosyncratic Speech?

What is Idiosyncratic Speech?

September 21, 2023

People with autism spectrum disorder (ASD) have a wide range of abilities when it comes to speech and language skills. High functioning individuals may be perfectly fluent, others struggle, and some may remain nonverbal and communicate through other methods. 

What is Idiosyncratic Speech?

For many children with ASD, a delay in language development is one of the first signs that they have a developmental disorder. Struggles with verbal communication may result from speech problems (difficulty pronouncing or forming words correctly), language problems (difficulty using words in coherent sentences), or both. 

Download your FREE guide on 

Assistive Communication Devices for Children with Autism

Oftentimes, challenges with social communication go beyond just verbal—a child may be unable to grasp the meaning of body language and physical gestures, like pointing at an object. 

Typically-developing children will seek out social interactions with parents and other people, allowing them to naturally grow in their language skills. Autistic children, however, don’t tend to engage with others as readily even at an early age, leading to deficits in their social communication abilities.

When speaking, autistic children may mix up pronouns, have a flat tone of voice, discuss repetitive topics, misunderstand slang and sarcasm, use pedantic speech (speech that is overly formal for the context), use echolalia (repeating things they’ve heard from others or in a movie), and more.

Another common language characteristic for people with ASD is idiosyncratic speech. Some sets of criteria for an autism diagnosis, such as the Autism Diagnostic Observation Schedule, include it as a symptom of the disorder. The American Psychiatric Association’s Diagnostic and Statistical Manual, Fifth Edition (DSM-5) also lists “idiosyncratic phrases” under “repetitive patterns of behavior” that potentially point to autism spectrum disorders.

What is idiosyncratic speech?

The Merriam-Webster dictionary defines an idiosyncrasy as an “individualizing characteristic or quality”. Based on this definition, it’s easy to see how “idiosyncratic speech” got its name, because a child’s use of this language typically comes from his/her individual experiences. 

When we’re talking about spoken language, idiosyncrasies are when someone uses normal words or phrases in an abnormal way—the word will be a real word in the speaker’s native language, but it won’t actually be associated with whatever he/she is referring to. The true meaning will only make sense to the speaker, and possibly those close to him/her. 

For example, let’s say an autistic child’s Aunt Mary always takes him to a certain park. In his brain, he links Aunt Mary with that park, so he may say: “Aunt Mary” instead of “I want to go to the park.” Most other people wouldn’t understand the connection, but it’s the child’s attempt at communication.

Children who use idiosyncrasies may also be prone to using neologisms, or made-up words that aren’t part of their native language. 

A study by Joanne Volden and Catherine Lord (1991) found that children with autism spectrum disorder use neologisms and idiosyncrasies more often than neurotypical kids or mentally handicapped kids. They “were more likely to use words inappropriately that had no phonological or semantic similarity to the intended English word”. 

Nobody knows the exact reason behind these differences, or even behind autism itself. But researcher Avital Haramy, who co-authored a study on autism in 2015, suggested that: “From a young age, the average, typical person’s brain networks get molded by intensive interaction with people and the mutual environmental factors … It is possible that in ASD, as interactions with the environment are disrupted, each [person with ASD] develops a more uniquely individualistic brain organization pattern.”

Special Offer

Don't miss out on the Autism Parenting Summit.
Click here to sign up now!

Language and communication skills affected by idiosyncrasy

Idiosyncrasy and other language deficits commonly found in people with autism impact one’s pragmatic language. This is the ability to use speech to communicate with others in an appropriate way. There are three major skills associated with pragmatic language:

Using language for different contexts

  • Adjusting vocabulary and tone based on the audience—speaking to a friend versus a new acquaintance, speaking to a toddler versus a high schooler, etc.
  • Adjusting vocabulary and tone based on the situation—giving a presentation at school versus holding a conversation at a birthday party, discussing something private at home versus in public, etc.

Using language for different purposes

  • Knowing the standard, polite ways to greet others, say good-bye, request something, etc.

Following social communication rules

  • Letting the other participants speak
  • Reading nonverbal cues, body language, and gestures
  • Staying on topic and introducing relevant new ones
  • Not spending too much time on one’s own interests

All of these skills are key to having a comfortable social interaction, but they don’t come naturally to children with autism.

Idiosyncrasy affects each of these categories. A child who exhibits this behavior won’t understand that not everyone has the same knowledge he/she has—like in the previous example, he doesn’t get that not everyone knows Aunt Mary always takes him to the park. Or he may have just not grasped the proper sentence structure for explaining what he means. This limits his ability to maintain a conversation and get his point across.

Can idiosyncrasy be treated?

It’s common for kids with ASD to receive speech therapy to address idiosyncrasy and other challenges. Speech-language pathologists can help determine what abilities a child needs to work on and form a strategy to improve his/her verbal communication.

Treatment measures for your child will depend on how advanced his/her development is and what’s behind his/her idiosyncrasies in speech. Therapists often use games, roleplay, and one-on-one conversation to work on various skills. 

Ideally, speech therapy should be accessed early in the language development stage to improve the chances of good outcomes later. Keep an eye on your child’s progress and inform his/her doctor of any possible delay or impairment so you can decide if interventions are needed. Of course, even if your child is older and outside the typical language development stage, it’s not too late to access treatment. 

Speech therapy can be beneficial even for kids with high functioning autism who mostly speak well, since the treatment usually addresses the nonverbal parts of communication, too.

What to look for in a speech therapist

In your search for a speech-language pathologist, the qualities you look for will obviously depend on your child’s needs. But in general, some of the most important criteria are:

  • The therapist should be experienced with autistic patients, especially autistic children
  • The therapist should be able to build a good rapport with your child and engage him/her in the learning process
  • The therapist should keep you, the parent, involved and informed so you know how to help your child at home

When treatment doesn’t work

Some autistic people never gain fully functional language, and that’s okay. There are other ways to communicate, such as:

  • Typing
  • Writing
  • Sign language
  • Picture exchange communication systems
  • Speech output devices that play pre-recorded words

As a parent, it’s natural to grieve if your child never reaches the speech milestones you expected. But all forms of communication are valid and none are lesser than verbal interaction, just different.

Download your FREE guide on 

Assistive Communication Devices for Children with Autism


Social interaction is an important part of life. Most of us can’t get through the day without holding a conversation, whether it’s with friends, family, or coworkers. If possible, it’s important for children with autism to work on their language skills so they can reach their potential and build stronger relationships with others.

Idiosyncrasy is a challenging problem that may be frustrating both for the child who wishes to be understood and those who want to understand. Luckily, progress in this area is possible. 

No matter what the outcome of your child’s speech journey is, he/she is a unique individual with his/her own abilities, strengths, and a special connection with his/her greatest advocate—you.


AppliedBehaviorAnalysisEdu.Org. (n.d.). How is ADOS (Autism Diagnostic Observation Schedule) Used to Identify ASD? AppliedBehaviorAnalysisEdu.Org. https://www.appliedbehavioranalysisedu.org/how-is-ados-autism-diagnostic-observation-schedule-used-to-identify-asd/

ASHAWire. (2015, March 1). Research Reveals ‘Idiosyncratic’ Brain Functions in ASD. ASHAWire. https://leader.pubs.asha.org/doi/10.1044/leader.RIB5.20032015.17

Autism Live. (2015, December 15). Autism Jargon: Idiosyncratic Language [Video]. YouTube. https://www.youtube.com/watch?v=oVuXyU04d04

Centers for Disease Control and Prevention. (n.d.). Diagnostic Criteria. Centers for Disease Control and Prevention – Autism Spectrum Disorder. https://www.cdc.gov/ncbddd/autism/hcp-dsm.html

Cincinnati Children’s Hospital. (2015). Pragmatic Language. Speech-Language Pathology. www.cincinnatichildrens.org/-/media/cincinnati%20childrens/home/service/s/speech/hcp/doctor-info/…/information-language-pdf-pragmatic-lan-6.pdf

Merriam-Webster. (n.d.). Idiosyncrasy. In Merriam-Webster.com dictionary. Retrieved June 17, 2021, from https://www.merriam-webster.com/dictionary/idiosyncrasy

Field, E. I. (2021, April 12). Echolalia Autism: Why Does My Child Repeat Me? Autism Parenting Magazine. https://www.autismparentingmagazine.com/echolalia-autism-child/

Lachman, M. (2021, April 12). Benefits of Speech Therapy for Children with Autism. Autism Parenting Magazine. https://www.autismparentingmagazine.com/autism-speech-therapy-benefits/ 

Prud’hommeaux, E., van Santen, J. P.H., Black, L. M., & Roark, B. (2010, May). Automatic Detection of Idiosyncratic Word Use in Autism Spectrum Disorders. International Meeting for Autism Research 2010. https://www.researchgate.net/publication/268144716_Automatic_Detection_of_Idiosyncratic_Word_Use_in_Autism_Spectrum_Disorders

Stephan, T. (2016). Guidelines for Choosing a Speech-Language Pathologist. The Hanen Center. http://www.hanen.org/Helpful-Info/Articles/Choosing-a-Speech-Language-Pathologist.aspx

Volden, J., & Lord, C. (1991). Neologisms and idiosyncratic language in autistic speakers. Journal of Autism and Developmental Disorders, 21, 109-130. https://link.springer.com/article/10.1007%2FBF02284755#citeas

Support Autism Parenting Magazine

We hope you enjoyed this article. In order to support us to create more helpful information like this, please consider purchasing a subscription to Autism Parenting Magazine.

Download our FREE guide on the best Autism Resources for Parents

Related Articles

Autism Parenting Magazine