How does having a good ear promote successful second language speech acquisition in adulthood? Introducing Auditory Precision Hypothesis-L2

Abstract In this paper, I first provide a brief review of how scholars have conceptualized, tested, and elaborated aptitude frameworks relevant to second language (L2) speech learning. Subsequently, I introduce an emerging paradigm that assigns a fundamental role to domain-general auditory processing (i.e., having a good ear) in L1 speech acquisition and proposes that the same faculty acts as a cornerstone of L2 speech learning (i.e., the Auditory Precision Hypothesis-L2). This hypothesis predicts that learners with more precise auditory processing ability will be able to make the most of every input opportunity, which will result in more advanced L2 speech proficiency. To close, I will provide suggestions on how scholars can assess L2 students’ auditory processing ability (e.g., our team's offline test deposited at L2 Speech Tools for Researchers & Teachers [http://sla-speech-tools.com/]) and discuss how the results can be used to maximize learners’ L2 speech learning opportunities via optimal, profile-matched training programs (e.g., explicit vs. incidental training; naturalistic vs. classroom learning; phonetic vs. auditory training).