Michael H. Long (1945-2021) was an American applied linguist whose career gave him unusual authority in both research-heavy SLA and the messier world of pedagogy. He taught at the University of Hawai'i and later at the University of Maryland, where he helped build one of the strongest SLA communities in the field and mentored a generation of researchers.
Long had the reputation of a hard thinker, a sharp critic, and a serious builder. He did not simply publish arguments; he built programs, shaped doctoral training, and kept pressing the field to be more rigorous than it was always comfortable being. His name is most closely tied to the Interaction Hypothesis, Focus on Form, and strong-version TBLT, and those ideas came attached to a very definite scholarly temperament: exacting, combative when needed, and deeply committed to getting the theory-pedagogy connection right. He spent more than two decades at the University of Hawai'i at Mānoa before moving in 2005 to the University of Maryland, where he directed the School of Languages, Literatures and Cultures and founded a doctoral programme in SLA, holding a chair there until his death from pancreatic cancer in 2021.
Two contributions anchor the work. The Interaction Hypothesis recast acquisition as driven by meaning-focused interaction, with negotiation, recasts, and feedback as the engine of development rather than comprehensible input alone. And with Yano and Ross he drew the simplification versus elaboration distinction (Language Learning, 1994), showing that elaborated texts comprehend nearly as well as simplified ones while preserving target forms and authenticity, a finding that still underwrites how materials writers handle input modification. His 1991 chapter "Focus on form: a design feature in language teaching methodology" reoriented methodology debate for a generation.