§1. The form of a piece or of a passage is determined by the relationship among its sections.
Phrase(-group), cadence, period
§2. A phrase is a somewhat self-contained musical statement, a “clause” of musical speech, ending with a cadence, or punctuation.
§3. A cadence is the more or less conclusive punctuation in the musical “speech” that ends a phrase.
§4. A phrase-group is a group of successive related phrases.
§5. A period is a phrase-group that ends with a relatively conclusive cadence—perhaps a musical analogy to the complex sentence.
§6. Periods sometimes consist of antecedent and consequent phrases or phrase-groups. ♦ An antecedent phrase(-group) opens the musical sentence; ♦ the consequent complements the antecedent and completes the sentence. ♦ In a parallel period, the consequent phrase begins like the antecedent. ♦ In a double period, the antecedent and consequent each comprise two phrases.
§7. An extension is music that extends a phrase (or period) beyond the moment in musical time at which we expect it to end.
(Rounded) binary and ternary form
§8. A piece in binary form ♦ has two balancing sections, and ♦ the second section as a whole is different from the first—in other words, it isn’t a restatement or variation of the first. A piece in ternary form ♦ has three balancing sections, ♦ of which the second is different from the first and the third.
§9. Similarly, sections of pieces that are self-contained and closed can themselves be in binary or ternary form.
§10. If the closing material in a piece (or section) is essentially the same as the opening material, the piece (or section) is rounded. Accordingly, one says that a piece (or section) is in rounded binary form or rounded ternary form. Musical factors that determine form
§11. The form of a piece (or section) is determined by a number of factors, all acting jointly. Among these are ♦ the “familiarity factor” (has the passage been heard before in the piece?), ♦ cadences, and ♦ texture.
§12. When a passage is repeated—when it occurs twice in immediate succession—the two statements together generally constitute one large (subdivided) formal unit.
Strophic form
§13. A song is strophic when each stanza is set to essentially the same music. The music that sets each stanza is called a strophe.
Musical form, -2-