In Dutch upper-intermediate EFL classrooms, not much attention is paid to purposefully acquiring new and more complex language in speaking pedagogy. Yet, when pupils expand their linguistic complexity (= linguistic repertoire), they will be able to communicate more effectively. With this research, we hope to create an awareness of the effect of complexity in oral communication among Dutch EFL pupils in upper-intermediate (pre-university) education and design a pedagogical approach that encourages them to use new, complex language. We hope to not only increase pupils’ linguistic complexity and proficiency, but also to increase their sense of learning and self-efficacy; lastly, we hope to contribute to research into increasing complexity in second language acquisition and education.