Semiformal EMLs are developed to facilitate the adoption of educational modeling languages (EMLs) and to address practitioners' learning design concerns, such as reusability and readability. In this article, SDLD (Structure Dialogue Learning Design) is presented, which is a semiformal EML that aims to improve controllability of learning design quality, one of the major concerns of practitioners that has not been previously addressed by EMLs. To address this problem, SDLD follows the proposals of Transactional Distance Theory (TDT). The adoption of this theory helps to measure, identify, and integrate the determinants of learning design quality in the creation of learning designs. Results from using SDLD showed that it improves the expressiveness of EMLs, especially in terms of the interactional facet of learning units and confirmed that it improves the usefulness of existing EMLs. In this context, SDLD represents, on the one hand, a first step toward the operationalization of the TDT. On the other hand, it is another way to facilitate the adoption of EMLs for their utility.