Thirty-two-bar form

This introductory section is usually 16 bars long and establishes the background and mood of the number, with a free musical structure, speech-like rhythms, and rubato delivery, in order to highlight the attractions of the main tune.

Some verses contained a second set of lyrics intended to be sung between repeated performances of the main chorus.

The introductory verse from "What'll I Do" by Irving Berlin is as follows: Gone is the romance that was so divine,'tis broken and cannot be mendedYou must go your way, and I must go mine,but now that our love dreams have ended...

[7] This is in contrast to the modern usage of the term "chorus", which refers to a repeating musical and lyrical section in verse–chorus form.

[9][full citation needed] It was commonly used by composers George Gershwin (for example, in "I Got Rhythm" from 1930[10]), Cole Porter, and Jerome Kern,[11] and it dominated American popular music into the 1950s.

The Beatles ("From Me to You" [1963] and "Yesterday" [1965]), like many others, would extend the form with an instrumental section, second bridge, break or reprise of the introduction, etc., and another return to the main theme.

In "South of the Border Down Mexico Way" by Gene Autry, "the A sections… are doubled in length, to sixteen bars—but this affects the overall scheme only marginally".