Effects of developmental language disorder and bilingualism on children's executive functioning: A longitudinal study.
Bilingualism offers no magic fix for executive function in DLD, but it does no harm and may add a slight edge once language skills are leveled.
01Research in Context
What this study did
Tessel et al. (2020) followed children with developmental language disorder, or DLD, for three years.
They asked: does growing up bilingual change how executive function grows in these kids?
They tested the same group every year from age 4 to 7 and compared bilingual and single-language homes.
What they found
Kids with DLD kept weaker executive function scores no matter how many languages they heard.
Only after the team removed the effect of poor Dutch vocabulary did a small bilingual edge appear.
That edge showed up earliest, around ages 5–6, then faded.
How this fits with other research
MLWhiteside et al. (2022) and Phillips et al. (2024) looked at bilingual autism samples and also found no harm — and a slight plus — for language or social skills.
Boets et al. (2011) tested Down syndrome and saw zero cognitive cost from daily second-language exposure, matching the null result here before vocabulary was controlled.
Together the picture is clear: speaking two languages does not hurt neurodevelopmental disorders, and may give a tiny boost once language gaps are accounted for.
Why it matters
You can reassure families that continuing both languages will not stall therapy.
Keep targeting core language; executive struggles in DLD run deeper and need their own plans.
If you test EF, control for vocabulary level or you might miss a small bilingual advantage.
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02At a glance
03Original abstract
BACKGROUND: Children's executive functioning (EF) is often negatively associated with a developmental language disorder (DLD) and positively related to bilingualism. However, both regarding children with DLD and bilingual children, findings are mixed and few studies have investigated the combination of DLD and bilingualism in relation to EF. AIMS: This study investigated the effects of DLD and bilingualism on children's EF development. METHODS: Monolingual and bilingual children with DLD and typical development (TD; N = 32 in each group) were tested three times with yearly intervals (MAGE = 71 months at time 1). Verbal and visuospatial working memory, selective attention, and inhibition were assessed. RESULTS: Monolinguals and bilinguals with DLD had weak working memory and inhibition skills at each time point compared to TD peers, which could partly be explained by verbal short-term memory limitations. Positive effects of bilingualism emerged when controlling for Dutch vocabulary and morphology skills, and were most pronounced at time 1. CONCLUSIONS: Monolinguals and bilinguals with DLD have similar and persistent EF deficits, which are partly secondary to verbal short-term memory weaknesses. Bilinguals performed better on EF than monolinguals when Dutch language knowledge was controlled for. This effect was found regardless of DLD and was most prominent at age 5-6 years.
Research in developmental disabilities, 2020 · doi:10.1016/j.ridd.2020.103782