The paper reports on a case study from a teaching experiment on the construction of meaning of integral at secondary school level, starting from the cognitive root of area. In the considered activity, students are faced with some graphs of functions and are asked to work in group to trace the corresponding integral functions. The analysis considers the gesture-speech relationship and is carried out integrating cognitive and semiotic perspectives. The aim is to study how gestures enter in the process of conceptualisation, in a context of social construction of knowledge. [For complete proceedings, see ED489597.]