chuckle

轻声笑、低声笑

He chuckled quietly as he read the message on his phone.

他看著手机上的讯息，轻声笑了起来。

暗自窃笑、偷笑

She chuckled to herself about the mistake all afternoon.

她整个下午都为那个错误暗自窃笑。

轻笑、低笑声

There was a soft chuckle from the back of the room.

房间后方传来一声轻笑。