Another voice, or, possibly, two voices, were laughing and talking back at him from within.

There was a startled silence, and then the voice actually laughed.

At first there was no response, then a rough voice laughed.

A voice laughed quietly in the branches above his head.

A soft voice laughed in the darkness, 'Hope is the power that comes from within.

The voice on the other end laughed heartily and said, "No can do."

Somewhere far away through the open window a drunken voice laughed once and then was silent.

The voice on the other end of the line laughed heartily.

In the back of her head, a small voice laughed.

The voice on the other side of the door laughed.