noun
sleep-learning; hypnopedia
The idea or practice of learning while asleep, often by listening to audio recordings. The term is more common in speculative or educational contexts than in everyday conversation.
睡眠学習で英語を覚えられるという話を聞いたことがある。
I've heard that you can learn English through sleep-learning.
彼は睡
He is skeptical about the effectiveness of hypnopedia.