It was an involuntary sound, caused by his indrawn breath.

A little sound, involuntary and wordless, broke from him.

I must have made an involuntary sound, for Severio shushed me.

Kaen leaned forward to look, and an involuntary sound escaped him.

Alien made an involuntary little sound and took a step backward.

Phonic tics are involuntary sounds produced by moving air through the nose, mouth, or throat.

Perrin made an involuntary sound in his throat.

Their noise even covered the involuntary sounds he made crawling through pebbles and brush.

Randall moved suddenly, hard and abrupt, and he made a small involuntary sound.

It was a short involuntary sound, and it hurt her aching head.