Does Language Develop Differently in Autism? Part 2


[Edited version of a post on the old Blogspot blog from 2015].

Experts have long claimed that autistic people learn and use language differently than other people. What is language in autism like, and is there anything unique about it at all? Morton Ann Gernsbacher, Elizabeth Grace, and I investigated studies done from 2000–2015 with every language skill at all ages. Details can be found in our book chapter, here.

Does language develop differently in autism? Yes and no.

We found that language delays are especially common in autism. However, autistic children with language delays do not differ from other children with equal language delays. Autism does not seem to fundamentally change how people use language in any consistent way.

Autistic Language is Often Delayed.

Studies often find that autistic children develop language more slowly than typically-developing peers, especially when it comes to spoken language. They may be late in speaking their first words, first combinations of words (such as“blue-car”) and first grammatical sentences [1–7].

According to parents, young autistic children say fewer words than age peers [1,8–14]. In fact, it is often concerns about late talking that lead parents to seek out a diagnosis [15].

Parents also often report autistic children understand fewer words [1,8,10,11,16–20].

However, parents can easily either underestimate or overestimate what a young autistic child knows. If a child responds with atypical words or body language, or does not respond at all, a parent may mistakenly assume the child does not understand.

Alternatively, a parent may think a child understands language associated with a routine when the child really only understands the behavior that accompanies it. For example, she might seem to understand the words “let’s go outside” but really only understands the parent taking her coat and shoes out of the closet.

Fortunately, we can measure children’s language understanding more objectively, by testing them directly. One way is through standardized tests such as the Peabody Picture Vocabulary Test (PPVT) and its equivalent, the British Picture Vocabulary Scale (BPVS); the Preschool Language Scale; or the Clinical Evaluations of Language Fundamentals (CELF). Many studies using such tests indicate delays in understanding language, not just speaking [8,9,10,17,20–29].

Autistic Language is Similar to that of People with Similar Language Skills.

Psychologists often draw a distinction between “delay” and “deviance.”

Delay is when a person develops in the same way as others, but does so more slowly. For example, someone with delayed spoken vocabulary might have the vocabulary of the typical two year old at the age of six. Deviance is when a person develops in a qualitatively different way. They might develop a different pattern of skills, or they might develop the same skills in a different order. For example, some people have claimed that autistic people have a unique difficulty understanding nonliteral language, such as metaphors.

A person with a disability could, in theory, be delayed, deviant, or both. So, do autistic people have “deviant” language, or are they just especially likely to be delayed?

In order to answer this question, we have to compare autistic people to those with similar levels of language development who are not autistic. Such comparison groups might include younger typically-developing children, late talkers, or children with specific language impairment. If autistic people are simply delayed, they will learn the same language skills in the same order as these “language-matched” peers.

And in fact, they do.

Autistic children do not have a unique difficulty with learning social or emotional words, or an advantage in learning words associated with special interests. They learn the same words in the same proportion and in the same order as younger typically developing children. For example, they are no less likely to learn words for people or social routines, and no more likely to learn words for vehicles[1]. They also are no less likely to say emotion words [46].

Autistic people also do not have any reliable difficulty with more complex language, such as telling stories or understanding nonliteral language, once their general language delays are taken into account. Autistic children in grade school learn to understand metaphors, draw inferences from stories, and structure their own narratives at the same age as language-matched peers [47–52]. Their level of language impairment, not their degree of autistic traits, predicts how much difficulty they have with nonliteral language [47–51].

Autistic children sometimes develop language for a time, then seem to abruptly lose it. This pattern is called “regression.” Some people have argued that regression is characteristic of, and unique to, autism.

Regression is hard to define and measure. However, it seems that only a subgroup of autistic children lose language this way. Interestingly, those who lose language were previously experiencing little or no delay [53,54].

Language loss also occurs in a seizure disorder called Landau-Kleffner syndrome. It is not unique to autism.

Some people have claimed that autistic children use language in unique ways . For example, they might exhibit echolalia (repeating what they or others say), or pronoun reversal (switching “you” for “me” and vice versa).

These characteristics appear to occur in only a small minority of autistic children, and are reported less frequently now that they are no longer included in the diagnostic manual. They also occur in other disabled groups.

Pronoun reversals do not occur in all autistic children, and they also occur in other populations (see my earlier post here, and Dr. Jon Brock’s here). Young typically developing children sometimes confuse first- and second-person pronouns for a short time while learning them [55]. Children with other developmental disabilities, such as Down Syndrome, also reverse pronouns [56]. Like these other groups, autistic children are more likely to have difficulty producing the correct pronouns when using more complex sentences, or complex types of pronouns [57–60].

Thus, pronoun reversals may be a normal part of early language development; it simply lasts longer in autistic children and those with Down Syndrome because their language develops more slowly.

Echolalia was once viewed as unique to autism. However, very young typically developing children also produced echolalia — that is, they imitate all or part of the preceding utterance without any change. As they get older, they produce less echolalia [61,62].

Similarly, autistic children also may produce less echolalia as their language improves. The majority of children who were reported to have “lost” their autism diagnosis by age nine had once exhibited echolalia [63].

A longitudinal study followed autistic and non-autistic children with language delay and measured their increase in language comprehension. During this time period, both groups became less likely to immediately repeat words exactly, and were increasingly likely to use “mitigated echolalia” — that is, making small changes to the repeated sentence to better express their desired meaning) [64].

Echolalia appears to be a stepping stone to full self-generated language, and it may last longer in autistic children when their language develops more slowly.

Some people, after observing young autistic children progress from repeating whole phrases unchanged to self-generated speech, have concluded that autistic children must learn language in an entirely different way than typically developing ones. Whereas typically developing children first learn what words mean and then how to put them together, autistic children first learn whole phrases, and only later learn what the words mean and what grammatical rules link them together. As far as I know, this hypothesis has yet to be directly tested with a large group of young autistic children. However, there is also nothing more than anecdotal evidence for it.

If every known population learns language in one way, the burden of proof must be very high to show that one group learns it in the opposite way.

What can we conclude about language in autism?

In short:

  • Autistic people’s language is heterogeneous. Their language ability at any given time ranges from the most delayed to the most advanced possible. Their rate of development ranges from virtually nil [44] to nearly ten times that of typically developing peers [42].
  • Language delays are common in autism.
  • Autistic language is “delayed, not deviant.” Researchers have yet to identify any characteristics of autistic language that are universal in autism or cannot be found in other groups. Autistic language is not unique, but continuous with typical development and language disabilities.


There are too many references to share here. See our book chapter for the full list.



Mosaic of Minds: A Disability Research Review

Emily Morson explains research on neurodivergent brains through the lens of cognitive neuroscience, SLP, & lived experience. #neurodiverseSTEM cofounder.