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When language does not speak for itself: research on Developmental Language Disorder (DLD)

Date of news: 2 September 2022

Learning a language is not something that comes naturally to all children: around seven per cent of children in the Netherlands have a Developmental Language Disorder (DLD). These children may have difficulty speaking or understanding language. Over the next three years, linguist Imme Lammertink will be researching the influence of the language environment on children with DLD. Her angle of approach is unique: she specifically focuses on the peer language input of children in regular and special education.

taalontwikkelingsstoornis (TOS)Developmental Language Disorder (DLD) is a cognitive developmental disorder in which language is not processed properly in the brain. A child with DLD therefore has great difficulty, for example, with producing or understanding language. Language researcher Imme Lammertink carries out research on children with DLD. ‘DLD has similarities with ADD and Autism,' she explains. ‘'It is something that affects you at a young age and persists throughout your life. It is therefore different from, say, a language delay: you often get over a language delay whereas that is not the case for DLD'

Special or regular education

Lammertink recently received a prestigious Veni grant from the Dutch Research Council (NWO) for research into the language environment of children with DLD. This research is needed to understand how children with DLD can best be supported. In the Netherlands, children with DLD either go to regular schools or special needs schools. ‘The form of education in which these children do best is under discussion', Lammertink explains. 'There are concerns that children with DLD who attend special education receive less rich language input from their classmates, because they are often in a class with many other children with language problems.’ In order to find out whether these concerns are justified (because they certainly do not have to be), Lammertink is going to chart the peer language input at both forms of education.

Unique to this project is the focus on peer language rather than the language input children receive from parents or teachers. Lammertink carries out her research at schools with children with and without DLD, in special and regular education, around the age of eight. Using an audio recorder, Lammertink records these children in two situations: when they are playing in groups and when they are performing a more scholastic task together, such as solving a math problem. In this way, a unique corpus of spoken language between children is built, providing an answer to the question of what the differences in the peer language environment are between special and regular education.


In addition to providing insight into the language input in the various types of education, the study should also provide more clarity about how the language development of children with DLD works. The focus here lies on researching recognising patterns in language, something that children with DLD seem to have difficulty with. Lammertink: 'There are fixed patterns in every language. The idea is that children pick them up themselves from the language environment. For example, you learn to conjugate verbs because at a certain point you realise that certain elements belong together: with "he walks" you see that the "he" and the "-s" are connected. Of course, in order to see that, it has to occur regularly in your language environment.’

Children with DLD do not seem to pick up on these patterns so easily: for example, they say "he walk" or "he walking" instead of "he walks". By means of an experiment, Lammertink investigates what role the quality of the language environment plays in this. She does this by having children with and without DLD learn fantasy languages and testing how they react to input with a higher and lower degree of pattern structure. ‘In this way, I hope to discover what we can do to ensure that children with DLD do recognise these regularities, which in turn makes learning language easier', says Lammertink.


Although DLD is present at an early age, it is often discovered quite late, because few people are aware of it. This is frustrating for the children, but also for their parents and teachers, who do not understand what is going on. Yet children can benefit greatly if DLD is discovered early. There are therefore more and more initiatives to create awareness, such as an International DLD Day. Lammertink herself also aspires to translate the results of her research to the general public, just as she did with her PhD research: she turned that into a comic book for classmates of children with DLD (Het Grote TOS-mysterie by Wouter Goudswaard en Imme Lammertink). Now she plans to develop an app in which children playfully learn to discover regularities in language by creating a structured fantasy language themselves, just like in the experiment. This app can then be used by children with and without DLD, so that classmates of children with DLD gain more understanding of the disorder.

Imme Lammertink studied Dutch Language and Culture and Cognitive Neuroscience at Radboud University and obtained her PhD at the University of Amsterdam with a project on children with DLD. In January 2023, she will start her research on DLD at the CLS research group First Language Acquisition at Radboud University.