Your song voice itself can shape and manipulate the flows of magic: this is the power of the spellsong. Spellsongs require no gesturing, and the incantation becomes more of an aria. Each time you purchase this Trump, you can simultaneously affect an additional creature with your spellsongs. If the spell has a target of self, additional targets must be allies. All spellsongs assume a distance of Near, even if the original spell states another distance.
Your targets must be able to hear you (deaf targets are immune and hearing impaired targets receive +4 on their saves). Likewise, creatures with no mental activity or means of hearing (e.g. amorphous, fabricated, plantlike, undead) are immune to the effects unless the spell is specifically targeted to that type of creature.
Your GM may restrict the spells which can be cast as songs, perhaps by spell essence or spell school (see the Magic chapter). A list of magic songs may be specific to the campaign setting in which the game takes place. At the very least, a list should include spells of a Compulsory, Illusory, or Perceptive essence.