Although much research has been done citing the benefits of using writing in mathematics lessons, little has been done that examines teachers' responses to writing about mathematics and how those responses may shape teacher attitudes about using writing in the classroom. In this study, I examined the experiences of six teachers as they explored mathematics in a graduate class in secondary mathematics education and prepared written reports for Internet publication. After analyzing their work and their responses on questionnaires and in interviews, I found that several of the participants struggled with using the technical vocabulary of mathematics in their writings and that some of them had differing beliefs about the use of the vocabulary. Based on these findings, I recommend that mathematics educators use activities that challenge teachers to view vocabulary as mathematical content and that hone their skills in using it in their writings. [For the complete proceedings, see ED584829.]