tremor - A slight shaking movement, such as one caused by an earthquake or instability; also a subtle or faint sign of emotion, such as fear or excitement in the voice or body.
Because he was nervous, his voice had a significant tremor during the presentation.
scintillating - Describing someone or something that is exceptionally witty and entertaining, and is intellectually or emotinally stimulating.
Her scintillating conversation captivated those she talked to at the dinner party, leaving them laughing and enjoying themseles.