This paper reports on a study that investigated the nature of the students' mathematical talk in an undergraduate mathematics study group. Study groups to support the learning of first year mathematics students are encouraged by mathematics educators. From nine recorded sessions, a session with a high quantity of mathematical talk and unfamiliar topics was chosen as a case study. The students used several different interactions but they developed mostly low level cognitive conversations. Four proposed causes limiting the cognitive level of the student's mathematical talk are the lack of prior preparation, avoidance of high level cognitive questions and the inability to recognise and then develop opportunities.