Fiddle tunes are primarily instrumental melodies, though some have words that can be sung optionally. Most originated as tunes for dancing, but people often play them today in social settings and performance that do not include dancing. Most fiddle tunes consist of two melodic parts, often referred to as the A and B part. Frequently the tunes are played in A A B B form, that is, playing the A part twice, then the B part twice. This form is repeated for as long as the musicians, or the dancers, care to continue.