Somniloquy is better known as sleep-talking.  Sleep-talking is very common in young children and decreases in prevalence with age.  I found this interesting: people who speak sign language have been known to sign in their sleep.  Sleep-talking is so boring compared to sleep-signing. If you’re sharing a bed with someone who’s sleep talking, you can just play some music on your headphones and ignore them.  But if you’re sharing a bed with someone who is sleep-signing, you can put on headphones and imagine that they’re rapping.