Design thinking has been propositioned to be interconnected to Dewey's notion of pragmatist inquiry and aesthetic experience. To address the need for empirical studies on design thinking in the classroom and add to our understanding of its characteristics, this study explored middle years' students' discourse as they worked through a design challenge. Design thinking has been proposed to rely on inquiry as well as language in the form of specialised vocabulary and representations but how these intersect has not been studied. In this study, discourse analysis of inquiry and design behaviours during a design task and pre- post-testing of scientific language and representations is compared across two groups, one that engage in a design task embedded in an inquiry science unit, and one that also engage in a community of inquiry (CoI). The two groups are referred to as Non-CoI and CoI groups respectively. The hypothesis that CoI can enhance both the design process as well as accurate use of scientific language and representation in a design context was shown by contrasting CoI and non-CoI group test outcomes and small group design task discourse analysis. In this study, design and inquiry processes were synergistic, mutually reinforced each other, and were co-constituted through imbrication. The findings of this study have implications for science teaching using design thinking in a middle years' classroom.