IV. Diatonic Harmony, Tonicization, and Modulation
Tonicization
John Peterson and Megan Lavengood
Key Takeaways
- Tonicization is the process of making a non-tonic chord sound like a temporary tonic. This is done with chromatic chords called applied chords, or secondary dominant chords (V(7)) and secondary leading-tone chords (viio(7)) borrowed from the temporary key.
- Applied chords are notated with a slash. The chord before the slash is the identity of the applied chord within the secondary key, and the chord after the slash is the chord being tonicized. It’s read aloud from left to right with the word “of” replacing the slash: V/ii becomes “five of two.”
- Applied chords nearly always involve accidentals, and especially accidentals that raise the pitch.
- Another way of thinking about applied chords is to imagine them as altered versions of the diatonic chord with which it shares a root (for example, ii becomes II♯, which is V/V).
Tonicization is the process of making a non-tonic chord temporarily sound like tonic. It’s accomplished using secondary dominant or secondary leading-tone chords (sometimes called applied dominant and applied leading-tone chords). First, we’ll learn how to tonicize the dominant, and then we’ll see tonicizations of non-dominant chords.
Tonicizing V
Analyzing tonicization
Secondary dominant chords (V(7)/V)
analyzes a passage that temporarily makes V sound like the tonic chord. extracts the two chords from that participate in the tonicization. We have a C7 chord moving to an F chord, so if we were to analyze these chords without considering the key signature or the context that provides, we’d say the two chords represent the progression [latex]\mathrm{V^6_5-I}[/latex] in F major ( ).
If we now reconsider the context that
provides, we can see that the F major chord functions as V in the excerpt’s home key of B♭ major ( b). Indeed, it’s the chord that creates the half cadence that ends the first phrase. We know that we haven’t changed keys here because, in addition to the half cadence being in B♭ major, the second phrase also begins in B♭ major (it repeats the beginning of the first phrase). The C7 chord, however, clearly doesn’t belong to B♭ major—that’s what the E♮ accidental in the bass tells us. As we determined in , the C7 chord is [latex]\mathrm{V^6_5}[/latex] of the F major chord. To represent that in the context of , we say that the C7 chord is “[latex]\mathrm{V^6_5}[/latex] of V,” and we write “[latex]\mathrm{V^6_5/V}[/latex].” In other words, the F major chord is V, and the C7 chord is the [latex]\mathrm{V^6_5}[/latex] of that V chord. We’ve just labeled our first secondary dominant chord!Secondary leading-tone chords (viio(7)/V)
Tonicization can also be accomplished using secondary leading-tone chords, as in
.
walks through how to understand the relationship between the two highlighted chords in
- If we were in G major, we would analyze these chords as viio7–I. Recall that when we learned about the leading-tone seventh chord, we discovered that it’s common to lower the chordal seventh in major to create a fully diminished seventh chord. That’s still true here (notice the E♭!).
- The passage in is in C major, so we would analyze the G major chord as V, rather than I. That means the F♯o7 chord is viio7 of the V chord. We write “viio7/V” and say “seven diminished seven of five.”
- The passage in adds a [latex]\mathrm{cad.^6_4}[/latex] to embellish the dominant. That’s why the viio7/V doesn’t resolve directly to V.
- The [latex]\mathrm{cad.^6_4}[/latex] resolves to V7 rather than the V triad. Now we’ve arrived at the passage in
Summary: Steps for analyzing tonicization
Chromaticism is an indication that tonicization may be present. Since only V(7) and viio7 (or, rarely, vii∅7—see note in sidebar) can create tonicization, one of the most helpful things for determining the label is to ask “what is the quality of the chromatic chord?” The quality determines the label: if the chord is a major triad or dominant seventh chord, it gets the label V(7). If the chord is a diminished triad or diminished seventh chord, it gets the label viio(7).
When you come across a chromatic note, stop and ask the following questions:
- Is the chromatic note part of the chord, or is it an embellishing tone?
- Part of the chord: move on to question 2
- Embellishing tone: label appropriately
- What’s the quality of the chord?
- Major triad or dominant seventh chord: secondary V chord; label is V(7)/x
- Diminished triad or diminished seventh: secondary viio chord; label is viio7/x
- To determine x above, ask: In what key is the chromatic chord V or viio? Then, determine what Roman numeral the tonic triad of that key would get in the home key of your passage. That Roman numeral is x.
Writing applied chords
Spelling
The video in
walks through the steps for spelling V7/V, viio7/V, and vii∅7/V in major and minor keys. We recommend you grab a piece of staff paper so you can follow along by pausing the video and trying the exercises yourself. The steps are summarized below:- Determine the root of the chord being tonicized
- Pretend this root is the tonic of a temporary key
- Spell the top Roman numeral in that key (either V7 or viio7)
Resolving
The leading tone of the applied chord is referred to as the secondary leading tone; the chordal seventh is referred to as the secondary seventh. These dissonances resolve just as they normally would in their own key.
One exception is that when the tonicized chord is itself a seventh chord (as in the progression D7–G7–C), the secondary leading tone may resolve down by semitone into the seventh of the following chord. In the example progression, this would create a nice chromatic line: F♯–F♮–E (
).The video in
walks through the steps for spelling V7/V, viio7/V, and vii∅7/V in major and minor keys. Like with the previous video, we recommend pausing to try each exercise on staff paper. The steps are summarized below:- Spell the secondary chord
- Follow the typical writing procedure to part-write, but think in the temporary new key to determine how tendency tones resolve
- Check accidentals (especially if in minor)
Tonicizing chords other than V
Overview
Any major or minor triad can be tonicized, not just V. Diminished and augmented triads can’t be tonicized, since there are no diminished or augmented keys. This means that every Roman numeral can be tonicized except viio and iio.
Analyzing various tonicizations
When chords other than V are tonicized, we follow the same steps for analysis that we learned earlier; the only difference is that there are now more possibilities for which chords can be tonicized. Be on the lookout for chromatic notes: these are signals that tonicization may be present!
As you might imagine, the frequency with which a given chord is tonicized is related to the frequency with which that chord generally appears. For instance, the dominant and strong predominant chords are quite common, so we also see those chords tonicized with some frequency. The vi chord, while less common than ii, IV, and V, also frequently gets tonicized. The iii and VII (minor only) chords are uncommon harmonies, and we tend not to see them tonicized frequently.
Tonicizing strong predominants
Tonicizing strong pre-dominants usually involves chromatic inflection of members of the tonic triad. For example, a tonic triad can easily be turned into a V7/IV chord by adding te [latex](\downarrow\hat7)[/latex] to the triad (
). Similarly, a tonic triad can be turned into viio7/ii by raising do ([latex]\hat{1}[/latex]) and adding te [latex](\downarrow\hat7)[/latex] ( ).
Tonicized deceptive motion
One striking way to use tonicization is to highlight a deceptive motion (
). Here, the dominant moves to viio7/vi before the vi chord arrives, which draws our attention even more to the absence of the expected tonic after the V chord.
Adding tonicization to diatonic progressions
The steps for part-writing tonicization remain the same as for tonicizations of V. Now, however, we should expect to see tonicizations of non-dominant major and minor triads.
shows a diatonic progression (a) to which several tonicizations have been added (b).
Secondary dominants as altered diatonic chords
Another way of thinking about secondary chords is to imagine them as altered versions of the diatonic chord with which it shares a root.
The most straightforward example is when a ii chord is chromatically altered by changing fa ([latex]\hat{4}[/latex]) to fi ([latex]\uparrow\hat{4}[/latex]) and then progresses, like usual, to the dominant chord. This alteration of fa to fi [latex](\hat4-\uparrow\hat4)[/latex] turns a regular subdominant chord into a chord that has a dominant function in the key of the dominant.
Take the chord progression Dmi7–G–C in C major, which we would label with Roman numerals as ii7–V–I. If we change fa to fi ([latex]\hat4[/latex] to [latex]\uparrow\hat4[/latex], F to F♯) in the first chord, we get D7–G–C. In the key of C, we might analyze this progression as II♯7–V–I(note the uppercase Roman numeral, indicating the change of quality; the sharp sign afterward further clarifies the raised third of the chord). However, we can also note that D major belongs to G major; it is a dominant-functioning chord (V) in the key of G—the key in which the following chord is tonic. In other words, we are borrowing the dominant chord from the key of G and applying it to the G-major triad. Thus, we can re-interpret the progression as V7/V–V–I.
Practice it!
summarizes secondary chords as they relate to diatonic chords with the same root.
- Applied chords worksheet, available in three slightly different versions:
- Version A (.pdf, .mscx). Asks students to identify and write applied V, V7, viio, viio7, and vii∅7 chords with Roman numerals and figures.
- Version B—without ∅7s (.pdf, .mscz). Asks students to identify and write applied V, V7, viio, and viio7 chords with Roman numerals and figures.
- Version C—jazz/pop focus (.pdf, .mscz). No ∅7s or figured bass; all chords in root position. Students identify and write chord symbols in addition to notation.
- All applied chords (.pdf, .docx). Asks students to write from Roman numerals and figured bass, write from a longer figured bass, and analyze a complete piece with discussion questions.
A chord from another key inserted into a new key, in order to tonicize a diatonic chord other than I.
A chromatic chord that temporarily tonicizes another key besides the tonic key, by taking on a dominant function in that new key.
A leading-tone chord that makes a non-tonic chord temporarily sound like tonic. Most often, secondary leading-tone chords are fully diminished, though occasionally they are half-diminished.
A temporary key within a piece that is overall in a different key. For example, a piece in A major may temporarily modulate to E major; E major is a secondary key within A major.
A symbol that alters a pitch, such as the sharp (♯), flat (♭), and natural (♮) symbols.
The process by which a non-tonic triad is made to sound like a temporary tonic. It involves the use of secondary dominant or leading-tone chords.
Relating in some sense to the chromatic scale. The term may be used to refer to notes that are outside the given key.
A 7̂ that is one half step below 1̂. The leading tone is diatonic in major keys, but requires an accidental in minor keys.
Refers to the seventh above the root of a chord. For example, V⁷ in the key of C is spelled G-B-D-F; F is the chordal seventh.
1. Write the entire bass
2. Write the entire soprano to make a smooth melody that interacts well with the bass. Choose active notes for the soprano above dominant-function chords, and remember you do not always need to write left to right.
3. Write the inner voices by asking, "What notes do I already have? What notes do I still need? Considering spacing and resolution, what note placement would give me the smoothest motion?"
A harmonic function that may either lead toward a dominant-function chord or back to a tonic-function chord. Subdominant function is most typically associated with the IV chord, otherwise known as the subdominant chord, and the II chord, otherwise known as the supertonic chord.