The information processing rate can be a barrier to listening because people are hardly ever capable of processing information as fast as most speakers speak. recent research shows that there is little connection between speaker rate and listening effectiveness. there is such a wide variety of processing abilities among people that no matter how fast or slow you speak, it will not be appropriate. people are normally capable of processing information faster than most speakers speak.

I believe the answer is: people are normally capable of processing information faster than most speakers speak.
This happen because in a single of sentence, most of the message is allocated within 50-70% of that sentence.
Because of this, audience often able to hear process the full information before the sentence even finished.

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