Phrasing
Somewhat related to emphasis is phrasing. This is the grouping together of words, phrases, clauses, and other units so that their meaning and significance may be easily grasped by a listener. As has been already said, pauses serve as punctuation marks for the hearer.
Short pauses correspond to commas, longer ones to colons and semi-colons, marked ones to periods. Speakers can by pauses clearly indicate the conclusions of sections, the completion of topics, the passage from one part of the material to another, the transfer of attention from one subject to its opposite. Within smaller range pauses can add delightful variety to delivery as they can signally reinforce the interpretation.
No speaker should fall into the habit of monotonously letting his pauses mark the limit of his breath capacity, nor should he take any regular phrase, clause, or sentence length to be indicated by pauses. In this as in all other aspects variety is the charm of speech.