As you are talking to a friend on your cell phone, you might find that you can't hear them because they are speaking very softly. If you ask them to "speak up," from a physical perspective you are asking them to ________ of the sound waves they are producing.

Question

Quizplus · Accepted Answer

Asking someone to "speak up" means you are asking them to speak louder, which corresponds to increasing the amplitude of the sound waves they are producing. The amplitude of a wave is directly related to its loudness or volume.

As You Are Talking to a Friend on Your Cell