Phrase Type: The Sentence

From Open Music Theory (Shaffer, 2019):

“The prototypical sentence is eight measures long and contains two four-measure [sections]. The first of these is called the presentation [and] the second is the continuation...”

Sentence Diagram (Click to see)

The sentence is a single phrase*. It is a tight-knit theme that contains a beginning, middle, and end.

*Schaffer calls the sentence a two-phrase theme. But there is only one cadence. For the purposes of this course, the sentence is only one phrase and the presentation and continuation are only considered sections of one phrase.

Beethoven – Piano Sonata No. 1, Op. 2, No. 1, Mvmt. I (1795)
(Recording on youtube)

The presentation of the sentence serves what we call an “initiation” function:

    • Novel melodic material (the basic idea) is presented and repeated (See “motive X” above)
    • The tonality of the theme is established through tonic prolongation.
    • Usually, the repeated basic idea is altered by transposition or slight motivic alteration (See above: motive X is harmonized by I and then V).

The continuation is the middle + end. It creates tension as a contrast to the beginning materials and establishes the harmonic cadence to end the phrase:

    • The middle of the phrase breaks down the primary melodic material and creates tension through:
        • Liquidation (breaking apart of the basic idea)
        • Fragmentation (shortening of the length of time established by the basic idea: if the basic idea is 2 measures long, the repeated material in the continuation is only 1 measure long)
        • Sequential repetition (see motive X in measures 5-6)
        • Acceleration of harmonic rhythm
        • Increased movement of surface melodic rhythm
    • This creates an acceleration into the cadence to end the phrase.
        • The ending cadential progression sometimes contains a descending melodic pattern.
        • The cadence usually begins with last chord of the tonic prolongation and ends with a cadential arrival.