"Oh," was all that came out, and it sounded idiotic.

Because the words he had been taught to use in childhood all sounded idiotic now.

"It may sound idiotic but I presume that one of you two is the culprit."

She knew she sounded idiotic, but it was so unexpected.

"Oh, dear, I sound idiotic even to myself, thinking that a woman who doesn't even exist is trying to tell me things in my dream."

She moved past him, into the living room, praying she could think of something to say that wouldn't sound idiotic.

This may sound idiotic, but in Greene's book, he says the "ideas directly apply to all constituents of nature."

'Cheer up,' he said, knowing it must sound idiotic but unable to think of anything more useful.

Bruce could not think of anything more intelligent to say off the top of his head, and immediately cursed himself for sounding so idiotic.

I know that sounds idiotic since we're on an alien planet, but it's the best I can do.