Here are five words related to sleeping in Japanese
1) 昼寝 hirune(afternoon) nap; siesta
[昼 hiru (noon; daytime) + 寝 ne (sleep)]
2) 寝不足 nebusoku
not enough sleep
[寝 ne (sleep) + 不 fu (negative; non-; note: this changes to "bu" after certain sounds) + 足 soku (sufficient; note: this is also the kanji for "leg" or "foot")]
3) 朝寝坊 asa nebou
oversleeping (in the morning)
[朝 asa (morning) + 寝 ne (sleep) + 坊 bou (boy; priest)]
4) 寝言 negoto
talking in one's sleep
[寝 ne (sleep) + 言 koto (word; say; note: changes to "goto")]
5) 寝ぼける nebokeru
still half asleep
[寝 ne (sleep) + ぼける bokeru (grow senile)]