David Pimm 
Routledge Revivals: Speaking Mathematically (1987) [PDF ebook] 
Communication in Mathematics Clasrooms

First published in 1987, this book examines mathematics school teaching from the perspective that it is a language – arguing that this can illuminate many events that occur in classes and highlight issues that may not have previously seemed important. The central concern is with the processes of communication as they are shaped by school conventions and the fact that it is mathematics being discussed. Speaking, listening, writing and reading are examined and analysed with the first half focusing on verbal interactions and the second half examining aspects of pupil written mathematics. Also explored is the nature of the mathematical writing system itself and how pupils gain access to it.