This paper stems from research on mathematics teachers' participation in a particular collaborative learning process that addresses the issue of mathematical communication and mathematical reasoning in relation to the teaching of algebra. Although results from the developmental research revealed changes in the working group's meaning making about mathematical communication and reasoning, whether these changes are long-term and influence the teachers' mathematics teaching over time remains unclear. The aim of this paper is to discuss possible theoretical frameworks and ways of understanding mathematics teachers' long-term learning about mathematical communication and reasoning by describing what they can learn in an organized community of practice (Wenger 1998) when working with key mathematical issues. I will use the data and results from the developmental research to design another study on long-term learning.