Sociocognitive theory views learning, including second language acquisition, as the progressive "alignment" of individuals vis-à-vis their ecosocial environments. In this article we first update sociocognitive theory in light of recent evolutionary/ecological research on learning/teaching: (a) Humans are evolutionarily "adapted to adapt" to myriad environments, placing a premium on adaptive learning, (b) human adaptation is effected substantially through "niche construction"--engineering environments to make them more adaptive, and then transmitting the results culturally, placing a premium on adaptive teaching, (c) both human learning and teaching are innate/instinctive, and co-evolved, and (d) there are many kinds of 'teachers' in the world. Second, we briefly review 3 approaches to second language acquisition/teaching (SLA/T) vis-à-vis sociocognitive theory: van Lier's ecological-semiotic approach, Schumann's interactional instinct, and conversation analysis. Third, we apply our theoretical perspective exploratorily to videotaped data of a Japanese learner/user of English as a lingua franca who is baking pastries with a Finnish friend. Our analysis includes 5 widely studied 'units of participation': activity types, routines, co-constructed tellings, repetition, and assessments. Analysis suggests that these constitute powerful environmental support structures yielding rich learning opportunities for SLA/T in moment-to-moment interaction. Fourth and finally, we discuss our results vis-à-vis our theoretical approach. We conclude by suggesting how our expanded view of teaching/learning might broaden SLA/T's 'pedagogical imagination.'