Are there different subtypes of language disorder?

Developmental Language Disorder (DLD) is a broad category that encompasses a wide range of problems (Bishop et al, 2017). Some students may struggle to formulate complex, or even simple sentences; they may miss off grammatical inflections indicating verb tense or number, or experience other grammatical difficulties. For others, a small vocabulary, alongside difficulties learning new words and understanding the connections between words seems to be the main issue.

Other students may have trouble following instructions, or remembering and understanding large amounts of spoken information, even though they know the individual words contained within it. Some may have good understanding and sentence formulation skills but have specific difficulties in the area of pragmatics.

I have one student, for example, with weak inference skills, who struggles to make himself understood, even though his oral sentences are basically okay. When he speaks, his thoughts come out in a jumble, and he fails to consider what his conversation partner is likely to know already, either giving too little, or too much information.

Do all of these students have the same problem? Or is the nature, and cause of their difficulties diverse? There have been attempts over the years to identify different subgroups within the broader category of DLD. You may have used the terms “receptive language disorder” or “expressive language disorder” yourself. The term “Pragmatic Language Impairment” has also been used to describe children with social and pragmatic difficulties who do not meet the criteria for Autistic Spectrum Disorder (ASD).

However, when a group of international experts met in 2016 to attempt to reach a consensus on a range of issues, they were unable to agree on different subgroup classifications. They observed that the categories of receptive and expressive language disorder were rather “gross” and that subcategories were not stable over time (Bishop et al, 2017).

In some longitudinal studies, researchers attempting to classify children into different subgroups found that those children moved fluidly between those groups over time (Paul & Norbury, 2012). So a child who was originally placed into a vocabulary group or a receptive language group might have ended up in a group for children with expressive language difficulties by the end of the study. This brings into question the integrity of these subcategory classifications, and the utility of imposing them on the broader category of DLD, at least given our current understanding.

What these results do seem to suggest, is that whilst language disorders are chronic, the way that they manifest appears to change over time. This is likely due to a mixture of internal shifts as well as external factors such as successful intervention, combined with the increasing demands of new contexts, which may reveal difficulties across other areas.

So, a child initially identified with oral language difficulties may gradually overcome those, only for difficulties with more complex written language to emerge as they grow older. Instead of treating these as two separate difficulties, it seems more likely that they are different manifestations of the same underlying problem.

Finally, just as language disorders do not divide neatly into different subtypes, the boundaries between different neurodevelopmental disorders such as DLD, dyslexia and ASD may be less clear-cut than is commonly assumed. Until we fully understand the underlying mechanisms beneath these conditions, we are limited to what we see on the surface.

For more information on whether there is a difference between language disadvantage and language disorder, please see my next post: https://secondaryschoolslt.wordpress.com/2026/03/06/language-disorders-is-there-a-difference-between-disadvantage-and-disorder/

Notes

Bishop DVM, Snowling MJ, Thompson PA, Greenhalgh T, CATALISE consortium (2016) CATALISE: A Multinational and Multidisciplinary Delphi Consensus Study. Identifying Language Impairments in Children. PLoS ONE 11(7): e0158753.

Bishop, D.V.M., Snowling, M.J., Thompson, P.A., Greenhalgh, T., and the CATALISE-2 consortium (2017). ​ Phase 2 of CATALISE: a multinational and multidisciplinary Delphi consensus study of problems with language development: Terminology. ​ Journal of Child Psychology and Psychiatry, 58(10), pp. ​ 1068–1080.

Paul, R. and Norbury, C. (2012) Language Disorders from Infancy Through Adolescence: Listening, Speaking, Reading, Writing, and Communicating. 4th edn. St. Louis, MO: Elsevier.