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The Sooner, the Better - Linguists Research Early Indicators of Developmental Language Disorders

The experiments investigate the movement of the tongue, among other things. Photo: Karla Fritze

The experiments investigate the movement of the tongue, among other things. Photo: Karla Fritze

Their vocabulary is small and expanding slowly, words are mispronounced, grammatical rules are not applied correctly – these and other symptoms in children may indicate a developmental language disorder. Such a disorder is especially noticeable in primary and preschool children. There is evidence, however, that measurable indicators of disordered speech development exist much earlier – in the first months of life. Researchers in the EU project network “PredictAble,” which started in October 2015, are researching methods for the early detection of language disorders and investigating which common hurdles exist on the path to language acquisition in various languages.

A typical ultrasound image appears on the screen in the Laboratory for Oral Language Acquisition (LOLA), but this black-and-white image is special. It shows tongue movement during speech. The measuring instrument, which looks like a joystick, is positioned below the chin. Children who come to the language lab to be examined by Stefanos Tserkezis are between 4 and 8 years old. The researcher wants to examine the position and shape of the tongue while children form specific sounds, the speed of their movements and the temporal sequence. This also includes examining the coordination of tongue, lip, and jaw movements important for articulation. The aim is to understand  the temporal and spatial organization of articulatory gestures in the acquisition of speech fluency and how this connects to the acquisition of reading skills. 

Looking for New Diagnostic Instruments

“Longitudinal studies show that indicators for being at risk for a language disorder can already be detected at birth,” explains Barbara Höhle, Professor of Psycholinguistics and “PredictAble” project coordinator. Such indicators become apparent in the way in which babies process linguistic stimuli. Language acquisition in children has been studied for 15 years in the Potsdam BabyLab. The linguists now know that four-month-olds respond to the specific intonation patterns of their respective language. Their ability to process this early language information is crucial for linguistic skills at a much older age.

PredictAble is an EU-funded Marie Skłodowska-Curie Actions Innovative Training Network. European researchers from the universities of Potsdam, Paris Descartes (France), Jyväskylä (Finland), and Pompeu Fabra (Spain) are working together with clinical partners and industry partner NIRx Medizintechnik GmbH. A total of 15 PhD projects are to be implemented within the network, four of them in Potsdam. The aim of “PredictAble” is to develop new diagnostic instruments for language skills that can be used in very young children. In addition to spoken language, the research project also focuses on reading acquisition.

Tserkezis is particularly interested in the last point. In his PhD project, he wants to use ultrasound measurements of tongue movements to examine to what extent speech production is linked to the ability to process written text. There is already evidence suggesting such a connection. Tserkezis divided his participants into two groups. One group consists of children from families in which no one was known to have dyslexia, and the other group of children have at least one  family member who does.

“There is a genetic predisposition to dyslexia,” says Tserkezis. Children with an affected parent or sibling have a higher risk of developing dyslexia. The measurements will show whether there are noticeable differences between the two groups concerning the tongue’s shape, its position when forming certain sounds, and the speed of movement. If these are measurable, this will be the first step towards a new early diagnostic method for dyslexia – before children are able read or write.

Different Languages, Identical Problems

This research concentrates on very early language acquisition but also uses a cross-linguistic approach. What are the similarities between language acquisition in Finnish, Spanish, French, and German babies? What are the differences? While intonation information is important for German babies, it is not for French babies. For Finnish babies, however, the duration of sounds appears to be an important speech feature. PredictAble researchers are looking for indicators and markers of language development disorders that are valid across languages.

“Our hypothesis is that the underlying problem is the same in all children, no matter what language they are learning,” explains Höhle. “Little research has been done in this field.” In order to determine general risk factors, the young researchers are examining Hungarian, Finnish, French, Spanish, Catalan, and English in addition to German. Tserkezis will also be conducting his measurements outside of Germany; he will spend five months in the U.S. at Haskins Laboratories at Yale University to study the language development of English-speaking children.

Studies are necessary to develop cross-linguistic diagnostic instruments that would identify those points in speech processing that are identical in all languages. Here is where the studies of Lilla Zakariás come into play. The PhD student is searching trade and scientific publications, diagnostic protocols and guidelines, and the Internet for standardized language tests for children, covering various developmental language disorders for all six languages in the network program. “We are here in Germany and know our tests, but we hardly know what is happening in other countries,” says Zakariás. While there are approximately 30 different tests in Germany and France, there are fewer in Hungary and Finland, for example.

From Theory to Practice

Zakariás examines exactly which parameters are measured by the various tests – speaking, reading, and writing skills or other cognitive abilities – and determines whether there is an overlap in terms of available tests between the languages. Her research not only provides an overview of all possible tests for the other researchers, but it can also help compare the results of individual studies conducted in the different languages. One can investigate, for example, whether vocabulary size is connected to IQ or other cognitive or social conditions, as well as whether relationships made apparent in one language are valid also in other languages. “Since languages differ, we cannot automatically transfer relations we found in one language to another," she explains.

This upcoming research is highly relevant for speech therapy practice, because the earlier the problems are detected, the sooner an intervention can start. “This can significantly shorten the duration of speech therapy, because the parents are also given advice and can react accordingly,” explains Astrid Fröhling, head of the Center for Applied Psycholinguistics and Patholinguistics Potsdam (ZAPP).

Fröhling, a speech therapist, considers linguistic issues from the practical side in particular. She works with patients suffering from speech disorders every day. She also knows, however, the importance of basic scientific research. “Before we can develop and establish therapies, we need the respective studies,” says Fröhling. “We need to know at what points we need to make adjustments.” ZAPP is already a long-standing partner for patholinguistic training of students at the University of Potsdam and is one of the clinical project partners that will ultimately ensure the transfer of scientific results into practice. The path will go from research to diagnostics and therapy. 

 

The Researchers

Prof. Barbara Höhle studied linguistics, psychology, and social sciences at the Technische Universität Berlin. Since 2004, she has been Professor for Psycholinguistics/ Language Acquisition at the University of Potsdam.

Universität Potsdam 
Humanwissenschaftliche Fakultät
Karl-Liebknecht-Straße 24–25
14476 Potsdam
Email: hoehle@uni-potsdam.nomorespam.de

Lilla Zakariás studied patholinguistics at Eötvös Loránd University and cognitive sciences at the Budapest University of Technology and Economics (Hungary).
Email: lilla.zakarias@uni-potsdam.nomorespam.de

Stefanos Tserkezis studied philosophy and psychology at the University of Ioannina (Greece) and child development at the University of Amsterdam (Netherlands).
Email: tserkezi@uni-potsdam.nomorespam.de 

Text: Heike Kampe
Translation: Susanne Voigt 
Published online by: Daniela Großmann
Contact for the editorial office: onlineredaktion@uni-potsdam.nomorespam.de