The whole conversation had an eerie quality, as we talked of life and death in flat monotones.
Her flat little monotone bothered him, and he realized she was still in shock.
The voice had been counting off in a flat monotone for the last two hundred seconds.
The flat monotone in which it was delivered by the almost motionless 'leader' didn't help either.
It was light and high-pitched, but the words were spoken in a flat monotone.
And yet, despite the inflammatory nature of it, Stone spoke in a flat monotone.
He had cool eyes, Roach, voice was a flat monotone.
He said, in the same flat monotone as always, "Yes, go on."
She spoke with the flat monotone of someone operating on autopilot.
When Daystrom spoke it was in a low, flat monotone.