Literature suggests that the mathematical language of teachers impacts a student's understanding of math concepts. When teachers unintentionally use ambiguous language, students' understanding of a subject can be negatively affected. We share background on specific instances in which teachers can create confusion with the language they use, and we investigate both pre-service teachers' and college algebra students' concepts of three common terms in mathematics: Solve, Evaluate, and Simplify by asking both groups to unpack their understanding of these terms through a writing prompt. We compare the language used by both groups in their definitions. Preservice teachers' reflections on their experience with the writing prompt are also examined to identify ways that such a task can help them identify gaps in their own understanding and in their thinking about student learning. [For the complete proceedings, see ED583989.]