The art of writing is different than the art of public speaking. That principle was addressed in several previous posts. 
Just as the art of painting is not the same as photography, so writing is different than speaking! They share common elements, but each art form has advantages and disadvantages in regard to the other.
However, let me establish one further implication of that critical axiom . . . .
You will not develop as a speaker / preacher by only reading commentaries, books, or sermon-formatted-books. You need to listen to and watch preachers preach; else you will sound like a book and speak like a book. 
That does not mean commentaries, books, or sermons that have been put into a grammatically correct book format are not useful. They are. But it does mean that if you are going to develop your skills as a “speaker”/preacher it takes hearing and seeing it done by some of the most effective speakers engaged in the art.
During COVID-19, I have had the opportunity to watch preachers like Dr. David Jeremiah. The sermons were apparently time-lagged. That is, the initial sermons were with a full audience in an auditorium setting – PreCovid. Finally, the format had changed, and he is standing on a stage alone – Posy-Covid.
The difference is clear! He sounds like he is reading from a book or manuscript and has lost the elements which mark the art of public address. Sadly, I want to say — “Just send me the book. I promise I will read it.”
Take away the audience, and the art of public address begins to morph into the art of writing. The lost presence of an audience and lack of feedback draws one into a writing style, removing some of the most important elements of working with an audience.
One of the values of watching and listening to preachers is a better understanding of the vocal variety, which marks effective public address. In Steven Smith’s book, Recapturing The Voice Of God, in a section titled — “Pitch, Rate & Volume,” Smith uses those three elements  as a metaphor for different Scriptural genres. Interestingly, in making that metaphor, he discusses how those three characteristics play into raising children — his son Shep.
As I was reading Dr. Smith discuss those elements in light of parenting, I was reminded of how effective Dr. Smith is in employing all of those vocal elements! Not to mention how visually-facially effective he is.
Dr Steven Smith
Watch Beginning @ 42:23 video
watch his mouth, the sound of those words,
his visual-facial clues!
Watch when he says — “He fires it.”
√ Now, only listen to the audio (slight different in content)!
√ Then, transcribe this area of the message, and you will have to grammatically format it to conform to the written art. You lose the vocal and visual value, which is intricate to the art of public address.
√ Then, merely read a transcript of that same portion!
Listening is a great aid to better understanding the art of preaching.
Watching will help you even more!
Both listening and watching are vital to developing as a preacher!
Listen to and watch good and great preachers!
By the way!
It is a great Analogy
Link: Dr. Steven Smith — Begin at 39:45 seconds
2. Unless you really get good at it! Some political figures are! Far fewer preachers are — see previous posts.
3. Without getting picky or developing those elements, I would say that there are more than three elements. As he unwittingly suggests by putting intensity in parentheses — “(think intensity)” — “intensity” is different from pitch or volume, but more of a combination of pitch, volume, and rate. One example of that is when one is upset with one’s child, but desirous of not fully expressing that emotion, and a parent clamps his mouth and teeth in a somewhat closed position and says — “Get over here now!” — with a smile on his face.
I would also suggest that other elements worth consideration are pause, resonance, cadence, and body (airness) play into vocal tone.