Mixing language with science to target "because" and "so" in preschoolers with DLD

As SLPs, we all love the intricacies of grammar… right? No?

Well, we at least love ourselves some good ol’ adverbial clauses, right? Anyone? Just me?

Ok, so maybe we don’t all share the same nerdy love of all things grammar, but we can probably all agree that complex sentences are essential for both conversation and academics, and that children with developmental language disorder (DLD)—who struggle to use and understand these sentences—need effective language intervention to learn them. Also, even for us grammar enthusiasts, complex syntactic constructions can be difficult to teach. So what do we do?

That’s where this single-case study* from Curran and Van Horne comes in. They hypothesized that recast strategies—which have been researched extensively for teaching morphology—would improve preschool children’s use of causal adverbials, specifically because (“I ate because I was hungry”) and so clauses (I was hungry, so I ate). Critically, the authors distinguish between kids being able to use the word “because” in their speech (which happens pretty early) and actually acquiring multi-clause sentences that express a cause–effect relationship; and we’re interested in that second, more complex skill.  

What’s great about this study’s approach is that it looked at causal adverbials in the context of science instruction, which relies heavily on understanding of cause and effect. After some baseline probes and some standard science lessons, the researchers provided 20 sessions of science instruction combined with language intervention, using visuals, recasts, and prompting for those so and because clauses. A typical recast might sound like this: 

Child: “The kite goed up. Wind pushed it.”

Adult: “The kite went up because the wind pushed it.” 

Wondering how they got the kids to produce these structures in the first place? They used prompts like this one for because: “She pushed air in. The plunger popped out. Why did the plunger pop out? Start with ‘The plunger...’”

So did it work? Well, six of the seven children improved in their use of because clauses, showing strong positive trends during the intervention phase, compared to control structures. So clauses did not improve significantly, maybe because they were less frequent or as the result of a possible “competition effect” between because and so. Finally, while the kids did learn the science content over time, it didn’t seem to be the result of language skills gained.

The authors sum it up nicely: “Multiclause adverbials can be effectively addressed in clinical intervention, even for children who do not yet possess significant written language or metalinguistic skills.” Larger studies could help to clarify some of these findings, but using recasts as a way to teach complex syntactic structures is a promising strategy for children with DLD.


*Single case designs have their own special place in research and are valuable tools for treatment studies. They can highlight individual differences (because group designs only look at mean differences), and because it’s pretty comparable to what SLPs are doing in the real world, they have high social validity. We still would love to see similar results come from a larger study design, but these smaller studies teach us a lot in the meantime.


Curran, M., & Van Horne, A. O. (2019). Use of Recast Intervention to Teach Causal Adverbials to Young Children With Developmental Language Disorder Within a Science Curriculum: A Single Case Design Study. American Journal of Speech-Language Pathology. doi:10.1044/2018_AJSLP-17-0164