We investigate the rationale for instructional decisions proposed by two groups of community college mathematics faculty (full-time and part-time), as they discussed animations of trigonometry classes that breached several classroom norms. Although both groups of faculty justify their decisions in similar ways, the way in which they talk differs. We used systemic functional linguistics to describe the differences we observed: part-time faculty's language is more tentative, which hints at their tenuous status in their institutions. These findings may explain the negative perception in scholarship towards part-time faculty but such perception might not be justified in the classroom. The findings of this study suggest that further research is needed that attends to both the social context and teachers as individuals to better understand teacher decision-making.