Harmony Signing is a gesture-based form of musical communication that develops collective creativity and supports the confident acquisition of aural and musicianship skills. It involves singing in response to gestures influenced by those of the Kodály method and by aspects of the pedagogy of Dalcroze. Significantly, participants take turns to lead the group, developing the capacity to convey musical ideas and understanding through multisensory, social communication and shared experience. This constant sharing of roles is essential to the means by which the pedagogy confers fluency, confidence, and a practical grasp of music theory.The foundation of Harmony Signing is the presentation of the three Primary Triads (I, IV and V), to which participants respond through voice-leading consistent with the Species counterpoint of Johannes Fux. Initially, these positions permit progressions that can be employed to accompany melodies which are either performed by ear, or directed with the right hand using Kodály hand-signs. But at this stage, musical exploration is confined to a single key or mode.The principal aim of this workshop is to illustrate how modulation can be conveyed through the introduction of signs that convey departure from the prevailing key. Initially, the addition of a Dominant 7th to the key chord demands resolution onto ‘old’ chord IV, which moves as a consequence to the tonic position, usurping ‘old’ chord I. A ‘tonicising sign’, the right hand pointing downwards to the new left-hand position, confirms that this replacement has taken place: modulation has occurred.Modulation to the Dominant, replacing chord I with ‘old’ chord V, is a more elaborate procedure requiring two steps, and the introduction of a further new gesture. Chord II is required, the sign for which involves the left arm moving outside the body horizontally to the left, the hand representing the thumb upward gesture of the Kodály sign for the sharpened 4th, fi. The ‘tonicising sign’ needs then to be applied in order to convey that a perfect cadence will follow in which ‘old’ chord V now occupies the tonic position. Again, a modulation has been completed.Employment of these two procedures opens up sequential progress through the relative positions of the circle of fifths: ‘flatwards’ through bringing the Subdominant into the Tonic position; ‘sharpwards’ through modulating via chord II to ‘old’ chord V.The workshop involves demonstration of these procedures followed by involving participants in learning how to employ them in leading the group.