A growing amount of attention has been given to examining the domain-general auditory processing of individual acoustic dimensions as a key driving force for adult L2 acquisition. Whereas auditory processing has traditionally been conceptualized as a bottom-up and encapsulated phenomenon, the interaction model (Kraus & Banai, 2007) proposes auditory processing as a set of perceptual, cognitive, and motoric abilities-the perception of acoustic details (acuity), the selection of relevant and irrelevant dimensions (attention), and the conversion of audio input into motor action (integration). To test this hypothesis, we examined the relationship between each component and the L2 outcomes of 102 adult Chinese speakers of English who varied in age, experience, and working memory background. According to the results of the statistical analyses, (a) the tests scores tapped into essentially distinct components of auditory processing (acuity, attention, and integration), and (b) these components played an equal role in explaining various aspects of L2 learning (phonology, morphosyntax) with large effects, even after biographical background and working memory were controlled for. (PsycInfo Database Record (c) 2024 APA, all rights reserved).