Musical phrases may posses a variety of durations, and composers may mix phrases of different lengths in the same piece. Popular music often follows a regular formal organization of phrases that all include four even measures, each of which contains four beats. The Romantic composer Wagner, on the other hand, developed a reputation for writing musical phrases that stretched on for so long that the listener cannot easily identify when one phrase ends and the other begins.
A harmonic cadence often helps define the end of a phrase. Cadences occur in music when the harmony, or chord progression, creates a sense of resolution. Some cadences provide only a partial sense of resolution and propel the music into the next formal section, while other cadences may lend a sense of finality not only to the phrase but to the song as a whole. The plagal cadence, or traditional "amen" chorus at the end of many Christian hymns, acts as one example of a cadence that signals the end of a phrase.
Call and response songs use a call and answer technique for organizing distinct musical phrases between two individuals or groups of people. This musical form clearly demonstrates musical phrasing because each section takes turns singing one phrase. The lead party issues a call, and the chorus or group ensemble responds with the answer. The leader's call often ascends in pitch, as if asking a question, and the response often descends or ends with a sense of finality, as if answering a question. Each statement by each party often consists of one musical phrase.
Wind and brass instruments and the voice require breath to support and sustain a tone. Because of this, musical phrases in these instruments remain limited to the individual's breathing capacity. While some woodwind players can master a technique known as circular breathing to create a seemingly endless musical phrase, most musicians who rely on an airstream to play stay within a maximum 16- to 20-second time span within which they can create an expressive musical phrase. String players, pianists and percussionists, on the other hand, can create phrases bound only by the player's endurance and the composer's imagination.