Jim Cummins is an Irish-Canadian applied linguist and Professor Emeritus at the Ontario Institute for Studies in Education (OISE), University of Toronto. For half a century he has been the most prominent voice in North American bilingual education, anchoring both its theoretical core and much of its policy argument.
Cummins is best known for two interlocking distinctions. BICS and CALP separates everyday conversational fluency from academic language proficiency, and the Linguistic Interdependence Hypothesis argues that L1 academic competence transfers to L2 once a threshold has been crossed. Together they provided bilingual-education advocates with both a diagnostic tool and a policy argument against pull-out English-only approaches that deny learners access to their L1 as a resource.