Since non-chord tones (NCTs) usually involve dissonances, understanding NCTs leads to understanding dissonance control in music. The proper control of dissonance usually involves specific preparation, dissonance, and resolution.

The material in this post is drawn from chapter 8 of the Roig-Francoli. You need to read that chapter. What follows is a very schematic explanation.

Passing tones (PT) are approached by step and left (resolved) by step in the same direction. PTs fill in the melodic gap of a third. Double passing tones are possible to fill in the melodic gap of a fourth.

Neighbor notes (NN) are approached by step and resolve by step in the opposite direction, returning to the original preparation note.

Both PTs and NNs usually occur on weak beats (or fractions of beats), but can also appear on strong beats (Accented PT; APT). They are also usually diatonic, but can occur as chromatic dissonances.

A neighbor group (NG) involves four notes: the starting consonant note, a step up or down to the first dissonant NN, a leap of a third down or up (opposite of the first motion) to the second dissonant NN, and finally a stepwise return to the starting note as a consonant again.

Anticipations (ANT) occur on weak beats or fractions. The approach to the anticipation can be anything; the resolution is the same note as the dissonant one. The anticipation is an early arrival of a chord tone from the next harmony.

Incomplete neighbors (IN) include several figures that we know by other terms (Escape Tone, Appoggiatura). The book is somewhat flexible with these terms, but the important thing to know is that an incomplete neighbor combines a step and a leap. An escape tone (ET) is a weak beat step to a dissonant neighbor note, and then a leap to a consonant resolution. An appoggiatura (APP) involves a leap to a strong beat dissonance (most often up), then a stepwise resolution.

Suspensions

Suspensions are comprised of three parts: the consonant preparation (P), the dissonant suspension (S) occurring on a strong beat or fraction, and a consonant resolution (R) down by step on a weak beat or fraction. Suspensions always resolve down by step. When you are looking to add suspensions to four-part writing, you look for descending stepwise motion in a voice.

There are only four types of suspensions, labeled by the interval content of their suspension and resolution. The four types are:

• 4 – 3
• 7 – 6
• 9 – 8
• 2 – 3 (bass suspension)

Also possible is a variation of the 9 – 8, the 9 – 6 which involves a bass change.

Retardations are similar to suspensions, except they resolve up by step to a consonance. Retardations also do not have the same limited interval types.