Based on a model of communication according to which not only words but also body signals constitute lexicons (Poggi, 2007), the study presented aimes at building a lexicon of conductors? multimodal behaviours requesting intensification and attenuation of sound intensity. In a corpus of concerts and rehearsals, the conductors? body signals requesting to play or sing forte, piano, crescendo, diminuendo were analysed through an annotation scheme describing the body signals, their meanings, and their semiotic devices: generic codified (the same as in everyday language); specific codified (shared with laypeople but with specific meanings in conduction); direct iconic, (resemblance between visual and acoustic modality); indirect iconic, (evoking the technical movement by connected movements or emotion expressions). The work outlines a lexicon of the conductors? signals that in gesture, head, face, gaze, posture, body convey attenuation and intensification in music.