So when the party that is being called answers, the caller could speak through the little microphone instead.

It lasted nearly two minutes, although the caller spoke not a word.

When the caller spoke, she didn't recognize his voice.

Later, the family received periodic telephone calls in which the caller never spoke.

The caller spoke for about three minutes, when screams were heard in the background.

The words sounded muffled, as though the caller spoke through a thick cloth.

Hilary could tell from his expression that the caller had not spoken.

While the caller is speaking, you are deciding whether to answer.

In the fourth one, the caller spoke with a normal voice.

Almost all the callers he spoke to had information that had to be bought and paid for.