keys — a s d f g h j k play a rising scale. hold several for a chord; the choir holds it with you.
vowel — the shape of the sound. ah is open, ee is bright and narrow, oo is round and dark. switch mid-note and the choir changes its mouth.
register — bass, alto, soprano. each sings the same notes in its own range.
swell — how the voices enter. low is a sharp attack; high is the slow bloom of a held breath finding the note.
drone — a sustained root chord beneath everything. space toggles it. chord over it.
a vowel is just a few frequencies emphasized at once — the resonances of a throat. give noise those same resonances and it speaks, though nothing breathes. this is a voice with no body. you have met one before.