[u]Explaining the dominant function. [/u]

Ok I was figuring that's what you meant. I can’t disagree for the most part. When you refer to penultimate you mean in a perfect cadence (V-I). Later you say that without the dominant chord music would be stagnant. A V-I cadence is meant to be played at the end of a phrase, placing it in the middle often cause a halt in music flow. The Progression V-vi is what will keep things moving, or change to relative minor as a deceptive cadence. So this is it’s function in the major scale, what about the harmonic minor where I can have a minor 6th chord (I6). Would you say that this chord must move down a 5th?

[u]Limiting possibilities. [/u]

This is where I disagree. A diminished chord is not a rewritten dominant. Re-writing is changing. Making a diminished chord and a dominant 7 chord a product of the same entity is only one chord. That’s shortening the perception not expanding it by making them the same. Truth is a diminished chord and a dominant chord are 2 completely different chords. Just because a interval exists in one chord and a different chord doesn’t make them the same chord. There is some altering going on to make what you say work. For it to be a match the diminished chord would have to add a b6 for it to be a dominant chord, and for a dominant chord to match a diminished chord it would have to drop a harmonic tone, or should I say “ROOT” tone. If you want to talk to me about mislabeling and misanalyzing chords, you should check what your writing. Like many modern musicians, you think your breaking the rules but really your not. Your just re-naming it.

[u]The I chords function.[/u]

There is only one other chord that has the same sort of function as the I chord and that’s the vi chord, or relative minor chord. The thing that makes a tonic chord is the fact that all the other chords will want to pull back to it, not very many chords pull back to ii, iii, IV, or (haha) viio. Modal writing is a different subject and a different lesson. The Principle above still stands. Now to think of every chord as being a function of I, every chord would be a modulation. A principle that should be understand but not consistently.

[u]Passing tone vs. leading tone [/u]

What terms? They’re right. I just don’t think you understand what I was saying. Passing tone and leading tone are 2 different terms. A passing tone is a tone(accidental) played between 2 natural notes. Over a D dominant 7 chord: b7-7-1 equals this C-C#-D. C# would be the passing tone.

[u]Suspension 4th[/u]

Again you misunderstand what I’m saying. I’m talking about a sus4 extension to a chord. This is what I mean by playing a 4th as suspension over a chord, or a suspension chord (Asus4).

[u]Dominants moving anywhere[/u]

Again you misunderstand me. I’m talking about what notes are not good to harmonize over a dominant chord, not altering it. Like a D# (#5) over a G dominant 7 chord. Doesn’t sound good at all.