She could hear the men around her cursing under their breath.

I heard Belasius curse under his breath as he let go my rein.

And then heard himself clearly for the first time, singing under his breath.

All the while he could hear Michael muttering curses under her breath.

I heard him swearin' under his breath when the ship backed away from the pier.

Now, walking here he thought he heard Jim whimper under his breath.

Silence could hear the pilot cursing continually under his breath.

Riker thought he heard her murmur something under her breath.

Before long, Amanda heard Tony mutter something under his breath.

I heard her say something, under her breath, and turned.