Communication without emotion has an ephemeral impact.
The message has to get to the audience, it must touch them and generate a positive change on them.
I think that the connection with someone (or with the audience) is an invisible thread of emotional content that unites emitter and receiver in any act of quality communication.
Speaking in public CAN NOT just be a matter of technique.
We speak in public to move (move comes from the Latin emovere which means to get in motion). We talk in public to cause some movement in others.
Authenticity, emotion and listening are the bridges that allows us to connect to others.
Language, body and voice must be connected at the same time with emotion so that a genuine connection with the public arises.
If the discourse does not connect with the public, it does not exist.