She tried to mask her anxiety and to sound light and casual.

I tried to sound casual and matter-of-fact about it, but towards the end my tone got rather flat.

He sounded altogether casual about having been a slave.

I'd worked hard at this scenario and thought it sounded casual and reasonable.

At the end of the long discussion it sounded perfectly casual.

That had sounded properly casual; just a bit thrown in on the spur of the moment.

"Yeah," I said, trying to sound casual and noncommittal.

I hoped my voice sounded easy and casual.

"It's called a tapestry," I said, trying to sound completely casual.

"I haven't thought about it," she replied, trying to sound light and casual.