You start with the Listener dedication in addition to all other character creation options you select. You've heard a Harmony sing out across the Horizon and felt your soul be shaped by it. You're connected to an enigmatic force that binds you to others and offers previously unknown possibilities.
Listeners come from any creed or walk of life -- how a Harmony chooses who should join its chorus is unknown. The public has mixed opinions on Listeners: skepticism, disbelief, reverence, fear, and indifference are all common reactions to seeing one in the wild.
Those who hear a Harmony become attuned to it. This gives the listener that Harmony's trait. You can have at most one Harmony attuned at any time. Should you be given the opportunity to become attuned to a different Harmony, you must choose only one to keep.
Spells and other effects can also have these traits, making them more powerful against creatures attuned to a different Harmony. Some spells and abilities have the choral trait. If you have a Harmony trait, when you use a choral ability you add your Harmony trait to it.