This paper gives an account of the modalities of verbal interaction between researchers and teachers in the ACE project (Arithmetic and Comprehension in Elementary School): what consideration is granted to others in discourse and what consideration is granted to others in cooperative didactic engineering work? Our research question is motivated by evidence of the effectiveness of the ACE research project in students’ learning. We hypothesise that this success is determined, at least in part, by a certain degree of success in the cooperation between researchers and teachers. Our aim is thus to identify elements of determination for a potential model designed to foster an ongoing commitment to cooperation and the development of a rich and fruitful professional dialogue for both teachers and researchers.