Sentence (music)

In the last fifty years, an increasing number of theorists such as William Caplin have used the term to refer to a specific theme-type involving repetition and development.

Especially before the latter half of the twentieth century, different musicians and theorists employ and define the term in different ways.

"[1] Among the simplest examples he gives are what he calls "duple sentences" -- themes (from Mozart's D major Piano Sonata and Beethoven's Third Piano Concerto) in which we find pairs of "balanced" phrases (four-bar "announcing phrase" ending in half-cadence, followed by four-bar "responsive phrase" ending with perfect cadence): to many modern theorists this kind of structure is called a period.

"[2] Arnold Schoenberg applied the term "sentence" to a very specific structural type distinct from the antecedent-consequent period.

In a sentence's first part, a statement of a "basic motive" is followed by a "complementary repetition" (e.g. the first, "tonic version", of the shape reappears in a "dominant version"); in its second part this material is subjected to "reduction" or "condensation" with the intention of bringing the statement to a properly "liquidated" state and cadential conclusion.