Science has never given much credence to claims that you can learn Chinese or French by having the instruction CDs play while you sleep. If any learning happens that way, most scientists say, the language lesson is probably waking the sleeper up, not causing nouns and verbs to seep into a sound-asleep mind.

But a new study about a different kind of audio approach during sleep gives insight into how the sleeping brain works, and may eventually come in handy to people studying a language, cramming for a test or memorizing lines in a play.

Scientists at Northwestern University reported that playing specific sounds while people slept helped them remember more of what they had learned before they fell sleep, to the point where memories of individual facts were enhanced.

In a study published online Thursday by the journal Science, researchers taught people to move 50 pictures to their correct locations on a computer screen. Each picture was accompanied by a related sound, like a meow for a cat and whirring for a helicopter.