Traditional, cognitive-oriented theories of English language acquisition tend to employ experimental modes of inquiry and neglect social, cultural and historical contexts. In this paper, I review the theoretical debate over methodology by examining ontological, epistemological and methodological controversies around cognitive-oriented theories. I also present a socio-cultural research study on English language learning in a Taiwanese indigenous school as an example for discussion. Findings suggest that non-experimental modes of inquiry that employ multiple methods for multi-layered analysis are productive and appropriate. Socio-cultural theoretical lenses and methodological instruments may liberate research in English language studies and broaden our understanding of English learning and teaching.