Tricky-Loops wrote:Now I still don't understand why V-I is a progression and V-ii is a retrogression...
Ok, I didn't really mean to hijack the thread here...
In functional harmony, chords can be grouped into classifications; the first classification or "dominant" group being V and vii, both of which "progress" to the tonic, I.
Next comes a second classification or "predominant" group which includes ii and IV. These "progress" to the first classification above.
And so on.
If the chords move the other way, from first classification (dominant) to second classification (predominant) for example, then we call that a retrogression.
A classification can also be skipped over (for example moving directly from a second classification (predominant) to the tonic, as with IV-I), and this is called an elision.