This article proposes a conceptual and measurement framework for postpubertal, L2 speech learning aptitude that is centered around domain-general auditory processing (i.e., representing spectral and temporal characteristics of sounds). To this end, we examine the construct and reliability of a battery of auditory processing tests by presenting the results of an empirical study wherein 100 participants took the tests twice. The findings showed (a) that the tasks tapped into multiple dimensions of auditory processing ability (e.g., perceptual acuity, audio-motor integration); and (b) that test-retest reliability ranged from "fair" to "excellent" (ICC [subscript (2,2)] = 0.4-0.8). Last, we introduce an offline version of the tests (deposited at "L2 Speech Tools for Researchers & Teachers"; http://sla-speech-tools.com/), provide a brief user manual, and invite researchers to use these tests to examine the role of auditory processing in various aspects of L2 speech learning (naturalistic vs. classroom, perception- vs. production-based practice).