History of developmental language disorder

Specific language impairment

For decades, children with significant language difficulties that could not be explained by hearing loss, intellectual disability, or autism were given the diagnosis of “Specific Language Impairment” (SLI). The term emerged in the 1970s and 1980s and became the standard label in speech-language pathology and developmental psychology.

The word “specific” implied that the language difficulty was isolated, affecting language alone while other abilities remained intact. This was clinically useful as a diagnostic distinction, but it was also misleading. Research consistently showed that many children with SLI also experienced difficulties with literacy, motor coordination, attention, and social interaction. The language difficulty was rarely truly “specific”.

The problem with the old name

By the 2000s, researchers and clinicians increasingly recognised that SLI as a term was causing problems. The “specific” label led professionals and families to expect a narrow, isolated difficulty, when in reality the condition often had broader impacts on learning and development.

The “impairment” framing also carried weight. It positioned language differences as deficits to be fixed rather than as part of a developmental profile that might need accommodation and support.

Perhaps most significantly, the SLI label was poorly known. Despite affecting approximately 7% of school-age children, making it more common than autism, public and professional awareness was strikingly low. Many children with SLI were never formally identified, and their language difficulties were attributed to poor parenting, low intelligence, or lack of effort.

The CATALISE consensus

In 2017, a major international consensus project called CATALISE brought together researchers and clinicians to address the terminology problem. Led by Professor Dorothy Bishop at the University of Oxford, the group recommended replacing “Specific Language Impairment” with “Developmental Language Disorder” (DLD).

The change was significant in several ways. “Developmental” acknowledged that the condition was present from early in development and persisted, rather than being a temporary delay. “Language Disorder” was more descriptive and less misleading than “specific impairment”. And the new criteria explicitly acknowledged that DLD could co-occur with other developmental conditions, removing the artificial requirement that language be the only area of difficulty.

Persistence beyond childhood

Another important shift in understanding has been recognising that DLD does not resolve in childhood. Earlier assumptions suggested that language difficulties were developmental delays that children would “catch up” from. Research has demonstrated that for many people, DLD persists into adolescence and adulthood, affecting educational outcomes, employment, relationships, and mental health.

Adults with DLD may have developed compensatory strategies that mask their underlying language processing differences, but the difficulties remain. Many adults with DLD were never diagnosed in childhood and have lived with unexplained struggles in communication, reading, and academic achievement.

DLD in the UK

Awareness of DLD in the UK has improved since the 2017 name change, though it remains lower than for conditions like ADHD, autism, or dyslexia. The Royal College of Speech and Language Therapists has advocated for better identification and earlier intervention, and DLD Awareness Day (held annually in October) has helped raise the condition’s profile.

However, speech and language therapy services in the UK are variable, and early identification can be inconsistent. Many children with DLD reach school without having been assessed, and the impact on their educational achievement and self-esteem can be significant.

Further reading on neurobetter

• Developmental language disorder - overview
• Co-occurrence
• Understanding diagnosis
• The language of neurodiversity

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