In this analysis, we will look at the first few measures of Auld Lang Syne, a traditional Scottish ballad.
First, we must determine the key. Since the key signature contains one flat, two possibilities exist: F major or D minor.
The first chord contains F--A--C, an F major triad. Since this is I in F Major, we are most likely in that key.
The next measure contains all F's, A's, and C's. Thus, all four chords are I. Since we would be repeating an analysis symbol, there is no need to write it again.
The first chord of the next measure contains C--C--E--G, a C major triad. Thus, it is a V chord.
The second chord contains a C--C--D--F. This doesn't fit nicely into a triad -- let's skip it for now.
The third chord is a duplicate of the first.
The fourth chord contains a C--Bb--E--A. This chord also doesn't fit into a triad. Let's skip it as well.
The next measure contains F--A--C. Again, all four chords are I chords.
The final measure contains a Bb--Bb--F--D, a Bb major triad. Thus, it is a IV chord.
Let's go back and analyze the chords that we skipped.
If we consider nonharmonic tones, the first skipped chord can be analyze as a continuation of the V with two neighboring tones.
The second skipped chord is trickier.
When voicing seventh chords, composers sometimes leave out the fifth.
Notice that the bottom three notes are the root, third, and seventh of a C dominant seventh chord. Only the G (the fifth) is missing.
Hence, we can analyze it as V7 with a nonharmonic A.
Since the A is approached by step and then skips, it is an escape tone.
This analysis is reinforced by the fact that V chords commonly resolve to I. Listen to these measures of Auld Lang Syne.