The Voice and Diction of Conversation : Page 77
Few people talk too fast. Since it is assumed that a certain mental alertness goes with speed, people are less hesitant about checking one who does so. Naturally, if ever so checked
one should mark it well. When one seems to talk too fast, the root problem usually is that one thinks too little, that one just rattles on, probably in strings of main clauses with little subordination. As soon as a speaker tries to get some significance into what he says, and to place his ideas in proper relationship to one another, the speed tends to adjust itself. It is not likely to gallop away with him. The greater danger is always some form of hesitation or stumbling or turtle wobble.