Does language develop differently in autism? Part 1

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

When autism first appeared in the “diagnostic Bible,” the 1980 Diagnostic and Statistical Manual, one of the few criteria for diagnosis was “gross deficits in language development” (APA, 1980). Autism was once associated with:

“marked abnormalities in the production of speech, including volume, pitch, stress, rate, rhythm, and intonation” (1987);

“marked abnormalities in the form or content of speech, including stereotyped and repetitive use of speech” (1987);

“delay in, or total lack of, the development of spoken language.” (1994, 2000).

Today, in the most recent version, language disabilities are not even referenced (2013).

So, as the definition of autism expanded, abnormal language development started out as a defining characteristic, then became an optional trait, and now is no longer part of the diagnosis.

This change might seem strange to most people exposed to autism in the media, and even many who know autistic people personally. After all, many autistic children still do not produce spoken language, and some people who speak fluently sound “odd” in their volume, pitch, or even choice of words. So, what is autistic language like? Has it really changed in the past forty-odd years, or have researchers and clinicians just deemed it less essential?

Morton Ann Gernsbacher, Elizabeth Grace, and I tried to find out. We read hundreds of papers on the topic that came out since 2000. These studies examined every imaginable language skill, in every imaginable age group, with every imaginable method. What we learned might surprise you. Details can be found in our book chapter here.

We discovered three major findings.

1. Autistic people’s language skills vary widely.

2. In general, autistic people are more likely to have language delays.

3. Autistic people’s language is similar to that of non-autistic people whose language is equally delayed.

Autistic Language is Variable.

Some studies do not find any difference between autistic people and age peers [3–7]. These studies range from toddlers to adults, and evaluate skills as various as spoken vocabulary, understood vocabulary, and quality and quantity of writing.

Typically, studies find a wide range of performance in autistic groups. The majority are often unimpaired. A minority may have significant delays [8,9]. Some examples:

• One group surveyed parents of a large sample of autistic toddlers with a wide range of IQ scores. Over three quarters of this group said their first words before 18 months, which is within the range of typical development. However, a little over 5% had still not spoken their first words by six years of age — a huge delay. [10]
• In a group of autistic children and teenagers, half understood an average number of words (based on receptive vocabulary scores on the BPVS). One quarter performed one to two standard deviations below average, and another quarter scored over two standard deviations above average. [11]

Standard scores often range from as low as four standard deviations below average to two standard deviations above [2,12–14]. Thus, autistic people can rank among the most language impaired — or the most verbally gifted.

When researchers measure the rate of language development, instead of ability level at a given moment in time, autistic people are similarly variable.

Sometimes, despite lower initial performance, autistic people develop language skills faster, and for longer, than age peers [1,15]. Vocabulary may even improve into adulthood [16].

However, different individuals have very different rates of language development. The graph below shows the growth in spoken vocabulary development for 35 autistic preschoolers [17]. Parents reported these children’s vocabulary (using the MacArthur-Bates Communicative Development Inventory) four times over two years.

All the children started with a spoken vocabulary of fewer than 60 words, but they ended up with very different vocabulary sizes two years later. Those with the steepest growth could say nearly 700 words at the end of the study; another group showed little change at all. All these children were the same age, with similar levels of autistic traits, and similar measured IQ. Interestingly, they were also all undergoing the same interventions — which included speech and language therapy.

Overall, it seems that language development can be slower than normal during the first few years of life [18], but more rapid later on. However, individuals differ so greatly that it would be hard to identify a “typical rate” of autistic language development.

Stay tuned for part 2, in which we summarize what’s different — and what’s not so different — about language in autism.

References

1. Anderson, K., Lord, C., Risi, S., DiLavore, P. S., Shulman, C., Thurm, A., et al. (2007). Patterns of growth in verbal abilities among children with autism spectrum disorder. Journal of Counseling and Clinical Psychology, 75, 594- 604.
2. Jasmin, E., Couture, M., McKinely, P., Reid, G., Fombonne, E., & Gisel, E. (2009). Sensori-motor and daily living skills of preschool children with autism spectrum disorders. Journal of Autism and Developmental Disorders, 39, 231- 241.
3. Goodwin, A., Fein, D., & Naigles, L. R. (2012). Comprehension of wh-questions precedes their production in typical development and autism spectrum disorders. Autism Research, 5, 109- 123.
4. A°sberg, J. (2010). Patterns of language and discourse comprehension skills in school-aged children with autism spectrum disorders. Scandinavian Journal of Psychology, 51, 534 -539
5. Henderson, L. M., Clarke, P. J., & Snowling, M. J. (2011). Accessing and selecting word meaning in autism spectrum disorder. Journal of Child Psychology and Psychiatry, 52, 964–973.
6. Paul, R., Augustyn, A., Klin, A., & Volkmar, F. R. (2005). Perception and production of prosody by speakers with autism spectrum disorders. Journal of Autism and Developmental Disabilities, 35, 205- 220.
7. Troyb, E. (2011). Academic abilities in children and adolescents with a history of autism spectrum disorders who have achieved optimal outcomes (unpublished master’s thesis, paper 189). Storrs, CT: University of Connecticut.
8. Jones, C. D., & Schwartz, I. S. (2009). When asking questions is not enough: An observational study of social communication differences in high functioning children with autism. Journal of Autism and Developmental Disorders, 39, 432 -443.
9. A°sberg, J., & Dahlgren Sandberg, A. (2012). Dyslexic, delayed, precocious, or just normal? Word reading skills of children with autism spectrum disorders. Journal of Research in Reading, 35, 20 -31.
10. Wilson, S., Djukic, A., Shinnar, S., Dharmani, C., & Rapin, I. (2003). Clinical characteristics of language regression in children. Developmental Medicine & Child Neurology, 45(8), 508 -514.
11. McCann, J., Peppe´, S., Gibbon, F. E., O’Hare, A., & Rutherford, M. (2005). Prosody and its relationship to language in school-aged children with high-functioning autism (working paper WP-3). Queen Margaret University College Speech Science Research Center.
12. Nation, K., Clarke, P., Wright, B., & Williams, C. (2006). Patterns of reading ability in children with autism spectrum disorder. Journal of Autism and Developmental Disorders, 36, 911- 919.
13. Joseph, R. M., McGrath, L. M., & Tager-Flusberg, H. (2005). Executive dysfunction and its relation to language ability in verbal school-age children with autism. Developmental Neuropsychology, 27, 361 378.
14. Ricketts, J., Jones, C. R. G., Happe´, F., & Charman, T. (2013). Reading comprehension in autism spectrum disorders: The role of oral language and social functioning. Journal of Autism and Developmental Disorders, 43, 807- 816.
15. Cariello, A., Bigler, E. D., Tolley, S. E., Prigge, M. D., Neeley, E. S., Lange, N, et al. (2011, May). A longitudinal look at expressive, receptive, and total language development in individuals with autism spectrum disorders. Paper presented at the International Meeting for Autism Research, San Sebastian, Spain.
16. Mawhood, L., Howlin, P., & Rutter, M. (2000). Autism and developmental receptive language disorder — A comparative follow-up in early adult life. I: Cognitive and language outcomes. Journal of Child Psychology and Psychiatry, 41, 547- 559.
17. Smith, V., Mirenda, P., & Zaidman-Zait, A. (2007). Predictors of expressive vocabulary growth in children with autism. Journal of Speech, Language, and Hearing Research, 50, 149- 160.
18. Landa, R., & Garrett-Mayer, E. (2006). Development in infants with autism spectrum disorders: A prospective study. Journal of Child Psychology and Psychiatry, 47, 629 -638.