Beyond a unidimensional view: The multilayered perspective on the implicit–explicit knowledge interface

In recent years, insights from cognitive psychology on unconscious learning have been applied to second language acquisition (SLA) research, proposing that unconscious knowledge gradually becomes conscious through repetitive experience. This perspective offers a reinterpretation of the interface between implicit and explicit knowledge in SLA, contrasting with the traditional view that explicit knowledge gives rise to implicit knowledge. While the phenomenon of unconscious knowledge becoming conscious provides valuable insights into the dynamics of knowledge acquisition, it also suggests the need to reconceptualize the traditional notions of implicit and explicit knowledge. This article aims to propose a framework that integrates recent insights on unconscious learning with traditional claims in SLA. Specifically, we propose replacing the unidimensional linear continuum view – which positions implicit and explicit knowledge as two ends of a single axis and conceptualizes second language development as a back-and-forth transition between these poles – with a multilayered knowledge view: The Hierarchical-Layer Model of Conscious–Unconscious Knowledge (H-L Model). This alternative model serves as a working hypothesis to better capture the multilayered and differentiated nature of linguistic cognition.