No word was ever as effective as a rightly timed pause.– Mark Twain’s Speeches (1923 ed.)
That impressive silence, that eloquent silence, that geometrically progressive silence which often achieves a desired effect where no combination of words howsoever felicitous could accomplish it…. For one audience, the pause will be short; for another a little longer; for another a shade longer still; the performer must vary the length of the pause to suit the shades of difference between audiences. … I used to play with the pause as other children play with a toy.
– Autobiographical dictation, 11 October 1907. Published in Autobiography of Mark Twain, Vol. 3 (University of California Press, 2015).