Explicit Knowledge and Processes From a Usage‐Based Perspective: The Developmental Trajectory of an Instructed L2 Learner

<jats:p>This article considers explicit knowledge and processes in second language (L2) learning from a usage‐based theoretical perspective. It reports on the long‐term development of a single instructed adult learner's use of two L2 constructions, the German Perfekt of<jats:italic>gehen</jats:italic>(“go,” “walk”) and<jats:italic>fahren</jats:italic>(“go by vehicle”), which was tracked over a period of more than 3 years. The results indicate that explicit knowledge and processes seemed to have a powerful impact on the participant's L2 learning and use, apparently enabling him to override the predicted bottom‐up developmental path in certain circumstances and take a top‐down approach instead. Specifically, it was found that the development of<jats:italic>fahren</jats:italic>was consistent with the predicted trajectory of moving from item‐based to more schematic constructions. By contrast, the participant's use of<jats:italic>gehen</jats:italic>was characterized by schematic constructions almost from the beginning, suggesting a shortcut facilitated by explicit knowledge and processes. Both potential benefits and pitfalls associated with this alternative learning path are highlighted. The findings are explicated with reference to usage‐based and complexity/dynamic‐systems‐theoretic concepts, thus offering an integration of explicit knowledge and processes in L2 learning and use into this particular theoretical framework.</jats:p>