Shared understanding is often achieved in communication interactions at the point in which the participants come to an agreement upon meaning. Without shared meaning, misunderstandings can lead to a breakdown in communication, and possibly failure on collaborative tasks. The purpose of the present study was to examine how students, preservice, and in-service teachers used different strategies to attempt to reach shared meaning during a spatial visualization task in a STEM instructional context. The data included 15 transcribed recordings analyzed through constant comparative analysis to identify the characteristics of the communication during clarification exchanges. Findings highlight three features of these exchanges: confirmation, rethinking, and misdirection. Within these exchanges, communication involved precise, technical language as well as analogous, everyday language to attempt to reach shared meaning. Exchanges that were successful (in moving toward task completion) illustrated the use of this language to affirm or move toward shared vocabulary. Unsuccessful exchanges (that hindered task completion) resulted from misunderstandings due to lack of shared language or meaning. Classroom implications for teaching and learning include recognizing that everyday language and technical language can potentially serve as points of confusion, and embracing the importance of accurately assessing and responding to students' current understandings.