Developmental language disorder in Vietnamese children is a big focus of our research at the BDC Lab. But why?
Children with developmental language disorder face a higher risk of problems with reading and academic achievement than children without the disorder. The effects are long-lasting and can even negatively impact professional outcomes in adulthood.
Fortunately, these effects can be reduced if they are diagnosed and treated at an early age. The tools needed to diagnose DLD must be in the language that the child speaks. But, for children in Vietnam, that doesn’t exist.
Before we begin, what is developmental language disorder?
Developmental language disorder (DLD) refers to language difficulties that cannot be explained by any other condition like hearing loss, brain injury, or autism.
Children with DLD often have difficulties with learning new words, combining words to form grammatical sentences, and connecting sentences to tell a complete story. They will also have difficulties with understanding words, sentences, and stories. As children grow older, these challenges can impact reading, schooling, and professional outcomes.
So…how do we start to identify DLD in children in Vietnam?
While standardized tests are not yet available for Vietnamese children, we can identify children with DLD by combining the following tasks: parent and teacher surveys, vocabulary tests, and children's stories.
These tasks have accurately identified children who are at risk for DLD in prior research. Together, they tell us how much vocabulary, grammar, and storytelling children understand and produce.
Why these tasks?
Click each header to find out.
What is (and is not) a concern about a child’s language development and use? Children spend most of their day with their parents and teachers after all.
How many words does a child know and say? Not doing well could indicate difficulty with understanding, learning, and using words, which supports broader language learning.
How does a child connect their words and sentences to share ideas? Stories can capture how children use their language in a realistic setting—like in conversations or during playtime.
Were Vietnamese children identified with risk for DLD, then?
Yes! Based on this study, about 7% of Vietnamese kindergarteners were identified with risk for DLD. This is similar to rates found in the United States and other countries, so it seems like this identification process that included parent and teacher surveys, children’s language samples, and vocabulary tests is just as useful in Vietnam.
Also like other studies, both children with and without DLD made mistakes on similar grammatical patterns, but the children with DLD made more mistakes. Basically, grammatical patterns that are hard for all children are even harder for children with DLD. In Vietnamese, those grammatical patterns seem to be classifier omissions (một mèo instead of một con* mèo) and argument omissions (con mèo bắt…).
What are our next steps?
This study was only the first step towards diagnosing DLD in Vietnamese children. Now, we are actively creating and validating better assessment tools for Vietnamese children.
Since this study was published, we have completed more research on DLD assessment tools for Vietnamese monolingual children:
- Diagnostic accuracy of sentence repetition and nonword repetition for Developmental Language Disorder in Vietnamese by Pham & Ebert (2020)
— Article summary available on our website!
- Optimizing a Vietnamese sentence repetition task using item response theory by Pham et al. (2025)
We are also running a project that includes monolingual children in Vietnam as well as bilingual children in the United States to see if there are ways to identify DLD whether a child is learning one language or two.
Additional resources
Access to Vietnamese vocabulary tests (Picture Identification and Picture Naming) and other assessment tools, scoring instructions, and training videos are available at VietSLP. Registration is required, and it will provide free access to evidence-based assessment tools and resources.
More information on the identification of DLD in Vietnam can be found in Pham et al. (2019). Contact Dr. Giang Pham (gpham@sdsu.edu) for access to the full article.
References
Pham, G. T., Choi-Tucci, A., Do, N., & Ebert, K. D. (2025). Optimizing a Vietnamese sentence repetition task using item response theory. American Journal of Speech-Language Pathology, 34(3), 1176–1192. https://doi.org/10.1044/2024_AJSLP-24-00381
Pham, G. T., & Ebert, K. D. (2020). Diagnostic accuracy of sentence repetition and nonword repetition for Developmental Language Disorder in Vietnamese. Journal of Speech, Language, and Hearing Research, 63(5), 1521–1536. https://doi.org/10.1044/2020_JSLHR-19-00366
Pham, G. T., Pruitt-Lord, S., Snow, C. E., Nguyen, Y. H. T., Phạm, B., Dao, T. B. T., Tran, N. B. T., Pham, L. T., Hoang, H. T., & Dam, Q. (2019). Identifying developmental language disorder in Vietnamese children. Journal of Speech, Language, and Hearing Research, 62(5), 1452–1467. https://doi.org/10.1044/2019_JSLHR-L-18-0305
The Bilingual Development in Context Lab is dedicated to investigating bilingual children who speak Vietnamese or Spanish at home.