This article describes a national school improvement project involving five compulsory schools for hard-of-hearing pupils, located in different parts of Sweden. Using action research, the teachers tried to change the communication patterns among the pupils by changing their own classroom practices, In this process the teachers tested and used different tools, such as writing, shadowing and facilitating each other, over a three-year period. The purpose of this article is to examine how tools used in action research can be used to promote learning in relation to the concept of the zone of proximal development. The theoretical framework of the study is based on action research, as a collaborative way of creating knowledge, and on sociocultural learning theories. The basic assumption is that teachers, by using different tools, also challenge each other's learning. The results show the importance of internalising tools that become owned by individuals or communities of practise. To be able to assume an active role in the zone of proximal development, and to produce knowledge collaboratively, a meaning-making process was needed. It was found that this could be realised if the participants had an awareness of how to function as a critical friend among colleagues. Furthermore, the results revealed that, by using different tools, different voices can be heard. Three categories of voices were identified.