According to research, one of the major problems for students beginning with their mathematics studies is the mathematical language. To investigate the process of language development, we interviewed a group of 15 mathematics students from a German university at seven different times during their first year of study. In this paper we focus on the aspect of using symbolical mathematical language when formulating theorem-like statements. Our results imply three types of students with respect to their development of mathematical language. Students of the first type seem to be able to use mathematical symbols correctly from the beginning, whereas students of the second and third type show severe problems and difficulties in their use of language. But while students of the third type show no real development and the majority of them dropped out of their studies, improvements in using symbolical mathematical language can be observed for those of the second type.