Vygotsky saw mental and cultural development as "mediated" by artefacts, including tools and signs. He used his "genetic method" to investigate higher cognitive processes in historical context. These insights are foundational to sociocultural theory, which is widely used in education research. However, since Vygotsky, communicative globalization has changed the conditions of theorization, research, policy and practice. Global convergence is characterized by extensive and intensive flows of people, messages, knowledge, ideas and money, and sudden, multiple and disjunctive changes. Educational activity is "glonacal" activity, shaped simultaneously in global, national and local spheres. This article argues that nevertheless, once developed to incorporate global phenomena into the genetic method and the notion of mediating artefacts, Vygotsky's ideas have much to offer the analysis of globally affected educational practices. This conceptual approach combines the spatial insights of globalization theory with the socio-historical relational understandings enabled by the genetic method. It is illustrated by a case study on the learning to teach English practices of a cohort of Vietnamese pre-service teachers during their practicum. Global flows, media and artefacts, which are used extensively by these teachers, articulate with national and local practices and conventions in innovative ways. (Contains 3 figures.)