35.1 Introduction

In the preceding chapters of this book we have been primarily concerned with the building blocks of music. Out of necessity, our discussions have been focused on the effects of relatively isolated musical moments. But in reality, of course, a typical musical experience lasts much longer than the brief examples included here. In other words, composers, performers, and listeners of tonal Western art music are primarily interested in entire pieces! And just as we may observe the structure and mechanisms of small spans of music, so too may we make analytical observations on a larger scale.

In this and the following chapters we will be talking about form, the structure and organization of musical composition. In the course of this discussion we will see all of the various dimensions of music coming together. Among these, though, melody and harmony will play the most significant roles since for many practitioners of this art the thematic content and the way it both projects and interacts with the underlying key structure is central to the musical experience.

Music theorists and teachers have traditionally conceived of form as being hierarchical in nature. The smallest musical elements—notes—combine to form ever larger units, eventually reaching the level of an entire composition. We have already introduced one level of this hierarchy, the phrase (see Chapter 22 and Chapter 24), so we will begin there. We will first look at how certain phrases are structured internally and then at how phrases combine to form larger sections of a piece.

35.2 Sentences

As we have already seen, phrases come in a wide variety of sizes and styles. But despite any superficial differences, many of them share a similar harmonic structure. The T–PD–D–T tonal phrase model and its variants describe a great many phrases throughout the tonal Western art music canon. (See Chapter 24 to review the tonal phrase model.) In some cases, though, the similarities between phrases go beyond the placement of harmonic functions.

Consider the following example, which consists of a single phrase:

When we analyze musical form we are primarily concerned with the interaction of the thematic as well as the harmonic content of a piece or passage—that is, with the pitches and rhythm of its melodies as well as the harmonic functions within its phrases and how they fit into the broader key structure. This phrase begins with a tonic triad in G major and ends with a half cadence in the same key eight bars later. Over the course of those eight bars, we hear the melody rise and fall above a series of sustained notes in the bass prolonging the initial tonic as it works its way toward the dominant.

In this phrase, the constituent parts of the melody are particularly interesting. Look, for example, at mm. 1–2. After the initial D on beat one the melody leaps down a perfect fifth to G. It then changes direction and fills in the gap between the first two notes with stepwise motion in eighth notes. In the second measure, we hear another leap down to G, which is then repeated on the third beat. Now look at the melody in mm. 3–4. Although the pitches have changed, the rhythm and melodic contour are immediately recognizable. The melody heard in mm. 3–4 is like an echo of the opening measures. Elements of this echo are present in the second half of the phrase as well. In mm. 5–7 we find the same rhythm as m. 1, though here the eighth notes are descending by step. These linkages in rhythm and contour tie the whole melody together.

Rather than a series of disconnected ideas, we hear a cohesive melody from start to finish. The entire melodic line is held together by the small musical idea presented in mm. 1–2. We refer to such an idea as a motive since it is presented as the melodic motivation for what comes after. Not all musical ideas are motives, only those that are repeated in some transformed state.

Compare Example 35–1 to the following:

Like Example 35–1, a motive is presented in the opening two measures. In this case, the motive consists of a tonic arpeggio in staccato quarter notes followed by a sixteenth-note-triplet figure. The motive comes back, transformed, in mm. 3–4, here arpeggiating a V7 chord and with the triplet figure transposed up a step. Despite these changes, the listener immediately recognizes mm. 1–2 as the motivation for mm. 3–4. When the phrase continues, we hear only the second part of the motive in m. 5 and then the transposed version immediately after in m. 6. As was the case Example 35–1, the motive evolves as the phrase moves toward the cadence.

Though sounding quite different on the surface, the phrases in Example 35–1 and Example 35–2 are remarkably similar in structure. They both start with a small musical idea, a motive, in the opening bars. The motive is then repeated with different pitches but a recognizable contour. The motive continues to develop in mm. 5–8 as the phrase drives toward the cadence. This particular phrase format is known as a sentence.

A sentence consists of two parts. The first part of a sentence is called the presentation. Usually four bars long, the presentation is itself further divided into two halves. The first half of the presentation presents the listener with a brief musical idea and the second half repeats that idea. When the idea is repeated, it is almost always transformed in some way. It may, for example, have different pitches or a modified contour; the rhythm may be altered in some way; or it may be re-harmonized. Regardless of the nature of transformation, the listener will recognize it as echoing the motive from the opening bars.

The second half of a sentence is called the continuation for it typically continues the motivic development of the presentation. In most sentences, the continuation is the same length as the presentation, usually four bars. Although the tempo typically remains the same, the continuation seems to increase in energy as it drives toward the cadence. More often than not, the continuation will feature fragmentation, a breaking down of the initial idea into even smaller parts, repeated at a faster pace, and enhancing the listener’s perception that the musical development is quickening.

The following diagram summarizes:

The individual parts are labeled to clarify the structure of the following sentence. (Note that the first four bars of the excerpt are an introduction and that the sentence does not begin until m. 5.)

As with the examples above, the germinating idea in this sentence is a two-bar motive (mm. 5–6) consisting of a triplet figure followed by four harmonic thirds. The idea is recognizable in mm. 7–8 even though the triplet figure is harmonized in thirds and with a different contour. The motive undergoes fragmentation in the continuation: it is truncated to just the first measure of the initial idea.

Usually, the repetition alters the basic idea in some way, but this is not a requirement. In the following sentence, mm. 3–4 repeat the basic idea note for note:

In other cases, the repetition may be far less recognizable. In the example below, the repetition of the basic idea switches from the right hand in mm. 1–2 to the left hand in mm. 3–4.

Note that while most sentences are eight bars long (2 + 2 + 4), these dimensions are not universal. At slower tempos a sentence may be four bars long (1 + 1 + 2) and at faster tempos sixteen (4 + 4 + 8). In other cases, the proportions may be skewed as a result of, say, an extended continuation. In the following example, the idea and repetition are two bars each—offset metrically to begin with an anacrusis—but the extended continuation is six bars long:

Now consider the following example:

Like Example 35–1, Example 35–2, and Example 35–4, this excerpt is eight bars long. A small musical idea presented in the first two measures is repeated with different pitches in mm. 3–4. Elements of this idea—the three eighth notes from m. 1 and the slurred descending thirds from m. 2—are developed in mm. 5–7 before the cadence in m. 8. In this case, though, the first four bars feel more or less complete, ending with an authentic cadence of their own in m. 4. The next four bars feel less like a continuation and more like the beginning of a new—but related—phrase.

It is important to remember that many terms like “sentence,” “presentation,” and “continuation,” were developed by music theorists after the music was already written. These concepts are designed to draw out connections between different works or different parts of a single work. They were not necessarily something the composer had in mind at the time they wrote the piece. You should not, in other words, try to force a piece or passage into a category. Use these terms to the extent that they are helpful and fall back on detailed descriptions to highlight interesting features and inconsistencies.

As with our discussion of the tonal phrase model, our purpose here is not to suggest that all such passages are the same. In fact, analyzing music in this way helps to draw out those qualities that make a piece or passage unique.

35.3 Periods

In discussing sentences, we looked at the interior structure of a phrase. But we may also look outward, to structures that contain more than just a single phrase. The excerpt below consists of two phrases in Bb major:

The two phrases in this example go together. The beginnings of the two phrases are nearly identical, leading the listener to hear them as an obvious pair. Where the phrases differ, though, is at their conclusions. The first phrase ends with an inconclusive half cadence. The second phrase ends with a much more conclusive perfect authentic cadence. If the music were to stop in m. 4, the listener would be left expecting something more.

Such a pair of phrases, where the second ends more conclusively than the first, is known as a period. In a period, the first, inconclusive phrase is called the antecedent and the second, comparatively conclusive phrase is called the consequent. To the listener, the effect is as though the antecedent poses a question and the consequent provides the answer.

In Example 35–9, the antecedent ended with a HC and the consequent with a PAC. This combination of cadences is common in a period, but there are other possibilities. For instance, a period may have an IAC in the antecedent followed by a PAC in the consequent.

In addition to the inconclusive/conclusive relationship heard between the two cadences, a pair of phrases must sound like they go together to be heard as a period. Example 35–9 was unambiguous in this regard since the two phrases began so similarly. When the antecedent and consequent of a period begin the same way, we call it a parallel period. Note that the differences between the left hand notes in m. 1 and m. 5 are not enough to dissuade a listener from hearing the two phrases as having the same beginning.

When the two phrases in a period begin in different ways, as in the following example, we call it a contrasting period:

As with Example 35–9, the antecedent in this period ends with an inconclusive HC and the consequent with a much more conclusive PAC. Unlike Example 35–9, however, these two phrases do not begin the same way. Compare m. 1 to m. 5 including the pickups. The right hand part is quite different in these two measures and yet we still hear these phrases as halves of a larger unit. The similar arpeggio figures in the left hand, among other things, dissuade the listener from hearing the two phrases as being completely unrelated.

The following example is a parallel period because m. 1 and m. 5 are identical. Notice, too, that the cadences are in different keys:

The antecedent in this period ends with a weak IAC in the home key of A major. The consequent begins in exactly the same way, but starts to diverge in m. 6. With the introduction of D# we hear the consequent straying from the original key, a move confirmed by the PAC in E major (the dominant key). The changing key does not affect our hearing of these two phrases as working together to form a period. Because it starts and ends in different keys, we refer to this as a modulating period.

The following example shows another modulating period:

This period has the same harmonic structure as Example 35–13: the antecedent ends with an IAC in the home key (F major) and the consequent ends with a PAC in the dominant key (C major). In this case, however, the two phrases do not begin the same way. The melody in m. 17 features an ascending figure followed by a repeated eighth note while m. 21 begins with a rest followed by a descending sixteenth-note scale segment. This, then, is a contrasting, modulating period.

There is one more characteristic to take into account when analyzing periods. In all of the periods discussed so far, the antecedent and consequent were equal in length. Keeping that in mind, consider the following example:

There is nothing surprising about the antecedent in this period. It is four bars long and ends with an IAC. The consequent, on the other hand, is not four bars long. The figures in the violin part and the right hand of the piano in mm. 5–6 are repeated twice in mm. 7–10 before moving on to the cadence in m. 12. Because the lengths of the antecedent and consequent are uneven, we refer to this as an asymmetrical period. (In an asymmetrical period, it is most common for the consequent to be the longer of the two phrases.)

To summarize, there are three criteria used in categorizing periods:

• parallel vs. contrasting
• modulating vs. non-modulating
• asymmetrical vs. symmetrical

Since a sentence is a format for a single phrase and since a period is a pair of phrases, it is possible for a period to be comprised of two sentences:

In this example, the first eight bars form a sentence. The basic idea is presented in the first two measures and repeated with slight variation in mm. 3–4. The next four bars—, the continuation—lead to a half cadence in m. 8. Then, beginning in m. 9, we hear the same sentence. This time, however, the ending has been altered to modulate to D major (the relative key) and end with a perfect authentic cadence. Overall, we may describe this passage as a symmetrical, parallel, modulating period, the antecedent and consequent of which are both sentences.

35.4 Double periods

The following example is comprised of four phrases, all of which work together to form a cohesive sixteen-bar unit:

The first two phrases (mm. 1–8) each end with a half cadence in Bb major on the second beat of the measure. The phrase-ending dominant is preceded by a pre-dominant ii6/5 in the first phrase (m. 4) and a cadential 6/4 in the second (m. 8). Beginning in m. 9, we hear the same material from the beginning returning with only slight variation. The cadence at the end of the third phrase, then, is the same half cadence heard at the end of the first. (Compare m. 12 to m. 4.) The fourth phrase, however, is slightly different. Instead of continuing to echo the opening phrases, the fourth phrase begins to diverge. (Compare m. 15 to m. 7.) This divergence leads to a PAC in m. 16, the only authentic cadence in the entire passage.

The return of the opening melody in m. 9 invites the listener to hear this passage in two eight-bar parts. In this hearing, the first eight bars act as an antecedent and the second eight bars as a parallel consequent. The entire sixteen-bar passage, then, may be heard as a period. A normal period, though, is comprised of just two phrases. Since there are four phrases in this period, we refer to it as a double period.

The following example shows another double period, this time in Eb major:

Like Example 35–17, this passage consists of four four-bar phrases. Also like Example 35–17, it is possible to hear this passage in eight-bar segments—though here the cadences in m. 4 and m. 12 are somewhat more pronounced. The first eight bars consist of two phrases, with an IAC in m. 4 and a HC in m. 8. The next eight bars are identical until m. 14, where the music is changed to lead to a conclusive PAC in m. 16. Overall we may hear this excerpt as a double period: a two-phrase antecedent in the first half with a two-phrase consequent in the second half.

The following table summarizes the cadence schemes of the double periods shown above. (These are the two most common formats for a double period.

While the cadence schemes listed in Example 35–19 are the most common for a double period, there are other possibilities. Consider the following example:

In this case, we hear three phrases ending with IACs followed by a fourth ending with a PAC. Compared to the IAC in m. 8, the PAC in m. 16 sounds much more resolved and so this passage fits our definition of a double period.

Identifying cadences is an essential part of formal analysis. In this regard, the two examples shown above are clear. In some cases, however, there are different ways of hearing a single passage of music. Listen to the following example and count the number of cadences you hear:

It is possible to hear this passage as containing just two cadences, each of which is signaled by half-note suspensions: a HC in Bb major in m. 4 and a PAC in the same key in m. 8. In this hearing, the excerpt would be considered a period with a four-bar antecedent and a four-bar consequent. It is also possible to hear this passage as being comprised of four phrases, each of which begins with a three-note pickup—the F–G–A eighth notes at the end of m. 42, m. 44, m. 46, and m. 48. In this hearing, the excerpt would be considered a double period with half cadences in m. 42 and m. 44 in addition to the cadences mentioned earlier. In a sense, the distinction between these two hearings is inconsequential. In both cases, the overall passage is heard as a period. Whether or not this is an example of a double period is a matter of subjective hearing.

Now consider the following example. Is this a double period?

Like the examples shown above, this excerpt contains four phrases: HC (m. 4), PAC (m. 8), HC (m. 12), PAC (m. 16). One might argue that this is not a period since both eight-bar halves end with equally conclusive cadences. In this hearing we would describe the passage as consisting of two separate but related periods, one after another. On the other hand, one might also argue that this passage is a (double) period. In this hearing, various details such as the lower register of the melody, denser chords, and descending melodic motion in both hands at the cadence make mm. 9–16 sound slightly more conclusive. Both of these arguments are valid, and rather than become overly preoccupied with categorization, you are encouraged to instead focus on the details as they appear in the music, for this is often what makes a piece unique and engaging.

35.5 Summary

The term form refers to the way a musical composition is structured and organized. Although all musical dimensions contribute to our experience of form, in analyzing this aspect of music we are primarily concerned with the interaction of thematic and harmonic content—of melodies and the way they work together with harmonic functions and key structures. In tonal Western art music, form is conceived as being hierarchical in nature, with small elements combining to create larger and larger units up to the level of an entire composition. Phrases occupy one of the intermediate levels of this hierarchy: we may observe both the interior parts of a phrase as well as the way phrases work in and with the surrounding music.

A sentence is a type of phrase that follows a particular thematic plan. A typical sentence begins with a motive, a small musical idea which will undergo various transformations. This idea is then repeated, usually with some variation in contour, rhythm, voicing, or harmonization. The idea and repetition together are referred to as the presentation, which comprises the first half of a sentence. The second half of a sentence is called the continuation, for it typically continues both the phrase and, in most cases, the development of the motive. The continuation portion of a sentence frequently includes fragmentation, a more rapid articulation of some recognizable element of the initial idea, heightening the dramatic energy of the phrase as it drives toward the cadence.

Looking beyond the scope of just a single phrase, we see that phrases can combine to form a period: a pair of phrases in which the second ends more conclusively than the first. The relatively inconclusive first phrase of a period is known as the antecedent. It usually ends with a HC or IAC. The more conclusive second phrase of a period is known as the consequent. It usually ends with a strong authentic cadence, in most cases a PAC though an IAC is sometimes used instead. Not all pairs of consecutive phrases form periods. If the second of two phrases ends less conclusively than the first or if the two endings are equally conclusive, the pair will not be heard as a period.

Periods are categorized according to several criteria. If the beginnings of the antecedent and consequent are thematically similar, they are said to form a parallel period. If the phrase beginnings are different, they are said to form a contrasting period. Some periods stay in a single key throughout while other, modulating periods begin in one key and end in another. In most periods, the antecedent and consequent are more or less equal in length; in an asymmetrical period, one of the phrases (usually the consequent) is longer than the other. A double period is one in which the antecedent and consequent are each comprised of two phrases.