Inflection
Explanation:
The public speaker has to be very aware of his audience as he delivers a speech and deliver accordingly the point they are trying to get across.
Through inflection a speaker changes their feeling and controls their craft to match with audience to deliver the desired effect they want to deliver.
This could be to shock a passive audience or to ride over an enthusiastic one with more aggressive words. It is impromptu and often done through oratory skills.
