Drawing upon observer participation in a first grade classroom, we present a systemic functional analysis of classroom communication located in relation to social semiotics, cultural historical activity theory, and ecological psychology, relating context to meaning making. Two years of observation include field notes, student assessments, audio and video recordings, photographic surveys, interviews and discussions with the teacher, her colleagues, and the school principal. Qualitative methods inform the coordination of the theoretical frameworks, incorporating their key concepts for a more comprehensive understanding of teaching, learning, and development than any one alone can offer. Extending the examination of variations in register to include the physical elements of context, we present four episodes occurring with distinctive registers of communication, social organization, and configuration of artifacts in space and time. The analysis spans scales of language, social organization, space, and time to expand the notions of register and cohesion. We introduce the concepts of contextual cohesion and semiotic proximity in explanation of the patterns we find in meaning making. (Contains 1 figure and 1 table.)