Looking to atypical populations to exhibit the functioning of core cognitive systems has a long history in the behavioral sciences (e.g., Caramazza, 1986; McCloskey, 1992). Pierce, Genesee, Delcenserie, and Morgan (2017) continue that tradition in their keynote paper, here by elucidating how the evolution of phonological working memory (PWM) may be molded not only by individual genetic variation but also by different features of the language acquisition context, whether that context is enriched, as in bilingualism; delayed, as with cochlear implantation (CI) or international adoption (IA); or impoverished, as with deaf children of hearing parents or repeat cases of otitis media. Their review of the literature shows that a sensitive (/critical) period for phonological evolution, encompassing variation in quality, quantity, and timing of early exposure, has pivotal consequences for an individual's level of PWM attainment and, by a compelling extension, for aspects of ongoing language evolution like vocabulary learning and reading skills.